Hobbyist Software provided me with a free copy of it's
iTunes Remote application for review. It allows you to control your iTunes on your Pre using your wifi network.
It's relatively simple to setup. First you install the server client (both a Windows and Mac version are available). This review is using the Windows client, because I don't on a Mac, although it should be a similar process for both. In Windows, small application stays running in your taskbar whenever your computer is running, although it is possible to hide the taskbar icon and then you can completely forget it's there. Once installed, you pair the server to iTunes, then pair your Pre to it all. It sounds complicated, but the software guides you and once it's done, you never have to deal with it again.

Hobbyist has also provided me with a beta version of the client app (the one that resides on your Pre) that's not hit the app catalog yet. This new version addresses one of the biggest complaints I've heard from people, the lack of an artist view. In it you can sort by playlist, artist, album and genre, giving you the same sorting options available from iTunes itself. Simply select an artist and it'll load up their songs into a playlist and start playing them. It also features a search, simply start typing in what you're looking for and it'll search your library for what you want.
Sadly the program isn't without its faults. Loading up an artist does not preserve the track numbers, instead it plays it alphabetically. Trying to play just one album from an artist, involves using album view because artist view displays all songs from an artist, instead of giving you an option of the albums from that artist. The application also tends to act up a bit when it loses its wifi link (something the Pre does anytime it goes into standby when not charging). But these are all minor issues and Hobbyist has shown they're very willing to improve and fix their product, as the early versions of this software had some much bigger issues that were quickly resolved. Hobbyist added a "News" section into the app for them to have easier contact with their end users and they encourage you to contact them with any issues.
Overall though, I can't recommend this product enough if you're a heavy user of iTunes. Personally, I have airtunes setup around my house so being out in the backyard and being able to switch the music coming over my speakers without coming inside is a great luxury, especially at the small cost of $4.99. If you currently use an iPod touch or an iPhone as your iTunes remote, it's time to make the switch. Hobbyist's software works just as well as Apple's version and it's only going to get better.