iTunesKeys is described as 'system-tray utility that lets you control iTunes with global hotkeys or from the tray icons menu while in the background'. There are four alternatives to iTunesKeys for Mac and Windows. The best alternative is SizzlingKeys, which is free. Other great apps like iTunesKeys are iTunes Volume Control (Free, Open Source), iTunesControl (Free) and ByteController (Free).
This little app allows you to control the iTunes volume using volume-up and "volume-down hotkeys from keyboard. It allows you also to control the same iTunes volume by means your Apple Remote. This is particularly useful to control volumes of AirPlay devices.
ByteController is a small user interface utility for controlling iTunes. ByteController gives you three buttons in your menu bar: Previous Song, Next Song and Play/Pause. Holding the Previous Song and Next Song buttons plays fast forward or rewinds.