M-RICK  Remote Buddy does even more for alsmot the same price ...  
(Version 1.2.2)

GCOGHILL  I'm confused—what does this do that the free Remote app for the iPhone doesn't do?  
(Version 1.1.6)

OSSIE  wifiTunes is new and freeware. Signal is a bit more refined, but worth $25?  
(Version 1.1.2)

M CHANG  Great piece of software. Some have suggested Remote Buddy and other free/openware. Signal does EXACTLY what I want it to do -- control iTunes from another room using iPhone. The app is fast and responsive, unlike Remote Buddy (which was bloatware and did a bunch of things, but the iTunes integration was not as good or fast).

A bit quirky (example: if you search by artist, find it, but if there is only one album by them and you add it, it does it alphabetical vs. in album order), but when you learn the workaround(s), it's quite nice.  
(Version 1.0.4)

AKRASTAN  Great when you are connected to your home sound system via AirTunes (on AirPortExpress) and your Mac stands in another part of the house.  
(Version 1.0.4)