Where to Look
As we mentioned before, the three best sources for finding a vacation rental are Homeaway, VRBO and Craigslist. All have their respective advantages and drawbacks. Interestingly enough, VRBO was purchased by Homeaway in 2006, so the two are basically an extension of the same site, though slightly different. So which is best for arranging your trip? Let's take a detailed look at each site.

VRBO
Vacation Rentals by Owner, or VRBO for short, was among the first sites on the 'net to offer property owners a resource to promote and advertise their rental properties worldwide.

• Benefits: VRBO has one of the widest selections of vacation properties of any site on the web, covering everything from major urban areas like Chicago and Barcelona to quiet countryside retreats. VRBO also recently began to note properties/owners that accept credit cards, meaning you can leave a deposit or pay in advance for many properties without the hassle of sending cash. Each listing offers a series of pictures of the apartment along with its amenities and anticipated price per night or week. Considering a multitude of good experiences we've had with the site in countries from Spain to Italy to Japan, we would have to recommend the site's enthusiastic and friendly property owners as one of the biggest advantages.
  
• Disadvantages: Although VRBO has an extensive database, in some cases it doesn't offer nearly as many units. A search of rentals in Barcelona, a popular vacation rental city, turns up around 100 properties, whereas Homeaway lists nearly twice as many in the city center. The site's layout can also be a bit confusing. Although you can sort rentals within a respective area or city by the number of beds and how many people it sleeps, it can be difficult to navigate.

Homeaway
Homeaway, along with VRBO, is among the biggest and most extensive vacation rental sites on the web, covering 120,000 rentals across 118 countries. In addition to purchasing VRBO in 2006, Homeaway also owns a number of other properties including VacationRentals.com.

• Benefits: much like VRBO, Homeway has an extensive, searchable database of properties worldwide. However, Homeaway really sets itself apart from VRBO in the search features, which are much easier to navigate. Users can select properties by categories such as number of bathrooms, type of property (villa, apartment, house, etc) as well as location type (near the beach, mountains, ocean). We're also big fans of the clean layout and easy to read pricing options, something VRBO doesn't always get right.
  
• Disadvantages: as far as we can tell, Homeaway provides no information about whether owners accept credit cards, which can be a real drag to discover when you arrive but certainly not a dealbreaker (PayPal is always a good backup).

Craigslist
In addition to being one of the world's leading places to sell your couch, pick up a date and scalp your tickets, Craiglist is also a good backup resource for urban-minded vacation renters. To take a look for yourself, click on the "Vacation Rentals" link under the "Housing" section.

• Benefits: Craigslist really shines for urban areas. If your trip will bring you to one of the world's bigger cities, you can bet Craiglist will have a couple vacation rental listings that might suit your style. The less stringent screening requirements mean you'll also find temporary and more fun/unusual properties that are not always listed on bigger sites like Homeaway or VRBO. Take that as a good thing or bad thing as you will.
• Disadvantages: the constantly updating information and postings on Craigslist also make for one of its biggest negatives. Though you can occasionally strike the jackpot, rentals on Craiglist can be hit or miss, especially if you're looking to find something in less developed/touristy country. The site also doesn't really screen its posters, so you'll sometimes have to be careful of the odd scam. It's also a bit annoying to realize that "Vacation Rentals" in Craigslist terms sometimes means those living in the city (not visitors) causing some confusion.

The Process
So how exactly do you go about renting one of these apartments anyway? And how do you know you're not just wiring funds to some shady guy waiting to take your money and run? Here's a few tips to ensure you find the vacation apartment of your dreams:

• The initial search - part of the fun (some would say annoyance) of vacation apartments is you can find a place that matches your style of travel. If there's a particular neighborhood you've heard you would prefer or you have specific requirements, run through a search to see what's available and average prices. Want to find a bohemian pad in Barcelona's Barrio Gotico? Perhaps something off Las Ramblas is more your style? Use the search filters to narrow to apartments in your preferred area. Don't forget to ensure you find a place that's big enough to fit your group, or somebody might end up on the couch (not that it's a bad thing).
  
• Check the calendar - rentals on both Homeaway and VRBO include an availability calendar (not always current) listing the dates the place has already been booked. Check your required dates to see if the place is free - if it looks booked up, best keep looking.
• Make contact - all three sites will offer a contact form to get in touch with the property's owner if you're interested. VRBO and Homeaway have extensive submission forms where you can add details on the length of your stay and number of guests. One of the keys of making contact is also to remember you're dealing direct with the owners. Make sure to be courteous and even if you have a wild kegger planned, don't mention it in the note, it's not going to help your case for the rental. Finally, contact multiple properties at once - you'll have a better chance of hearing from someone and locking something down.
• The deposit - Congrats, you found a place and it's free for your trip! Now you need to reserve. It's fairly standard to put some portion of your bill down in advance as a deposit, typically by a money service like PayPal or in some cases by credit card. Don't be afraid of passing along money - both Homeaway and VRBO extensively screen their owners and offer guarantees up to $5,000 if it turns out your deal was a scam. If you're really concerned, consider using a credit card, as you'll have better luck disputing charges if something goes awry.
• The arrival and stay - your trip is here and you've arrived at your destination. If possible, try to arrange a meetup in advance. Whenever possble I try to get the owner's mobile phone number and have a backup plan - it can be a real hassle to show up in a strange place and discover you missed your meetup and can't get in touch. Try and look the place up on a map beforehand as well - apartments in Europe are notorious for hidden entranceways and strange side door entrances.
• Be respectful - one of the keys to any successful relationship is trust. Consider it as if the owner has given you a key to their own home (sometimes they literally have) and treat the property with respect - this isn't a hotel room. And unlike a hotel, don't forget your rental will frequently come with neighbors as part of the deal - get too noisy and you might just get a complaint or two, so take the rabble rousing down the street to the bar.