Since x-tunes looks dead, I've taken to doing this, to try to emulate its functionality as much as possible.
1) Installed QuickSilver http://www.macupdate.com/info.php/id/14831
2) Installed the iTunes plugin for QuickSilver.
3) Installed Growl (http://www.macupdate.com/info.php/id/15979)
4) Installed the Growl plugin for QuickSilver
5) Configured the action keys for the QuickSilver iTunes plugin so I can set the rating on a song, increase/decrease volume, move to the next song, stop playing using keystrokes available from any application. With growl installed, I have it set to post a little transparent notification window for each new song it plays. Alltogether it works great and almost replaces x-tunes.
My keystrokes, for example:
ctrl+opt+cmd+1 rating of one for currently playing song
ctrl+opt+cmd+2 rating of two for currently playing song
ctrl+opt+cmd+3 rating of three for currently playing song
ctrl+opt+cmd+4 rating of four for currently playing song
ctrl+opt+cmd+5 rating of five for currently playing song
ctrl+opt+cmd+0 no rating for currently playing song
ctrl+opt+cmd+. Stop playing
ctrl+opt+cmd+? Show me which song is playing
ctrl+opt+cmd+UPArrow Play the earlier song
ctrl+opt+cmd+DOWNArrow Play the next song
ctrl+opt+cmd+= Increase volume
ctrl+opt+cmd+- Decrease volume
plus, QuickSilver is an amazing application.