Infinitely cooler and more practical than the still-respected iTunes Remote is Air Mouse for iPhone 1.5 ($6). Why? You can play music and videos from any media player, for starters, not just from Apple's pet player.
In fact, Air Mouse gives you the reins to the keyboard and mouse, with new screens in this version that are tailored to commanding the Web browser, media players, and function keys. Then there are the two methods for wielding your iPhone's remote mouse, and new support for landscape mode.