Like it or not, the iPod/iPhone has become a gaming platform. There are tons of statistics out there and I'm not going to bore you with them, but the fact is a lot of people are making games for the iPod and a lot of people are downloading and playing them. This post is not about educating the blog-reading public so much as a friendly word of advice to the game developers out there.
iPod game developers, remember what your platform is. No matter how Apple dresses it up or the media hypes it, the iPod is first and foremost a portable music player. The iPhone is just an iPod that also happens to make phone calls. So please, when you want us to play your games on our personal music players, do take care when shutting off our music.
Just using the examples that are currently on my iPod Touch, the biggest offender is probably Scramble Live, Zynga's Boggle clone. There is no music in the game and very minimal sound effects, so why does clicking the icon automatically shut off my music? Are you worried that listening to Nas will distract me from finding words, and if so isn't that really more of my concern than yours? Scramble is clearly designed for short bursts of casual play, so every time I play a round on the train I have my music interrupted, then end the game and go back to start my music all over again. Not cool. The same goes for THQ's de Blob. The game does thankfully use the same wonderful music as the infinitely better Wii game (sans player interaction) but it asks you upon loading the game if you want sounds enabled AFTER it has already stopped the music. Why offer sound options after turning off the preexisting sounds? Just set sounds to "on" and I'll mute my iPod if I don't like them. Or better yet, let me paint the town red to the Replacements!
Some games get away with it because the music is so integral to the gameplay, as you'd think it should be on an iPod game. 
Newtonica, for example, has an incredibly simple gameplay mechanic in merely flicking a sphere around to catch crystals in the correctly colored quadrants, but without the bright and lively electronic soundtrack it would be dreary and impossible to play for more than ten seconds. Radio Flare plays like a 2D side scrolling Rez by targeting up to four obstacles or enemies at a time and blowing them all up in beat with the music. Neither game has a soundtrack I'd listen to on its own, nor particularly interesting gameplay, but the play and the audio element work perfectly together to make them compelling. Both games force my iPod to stop playing music, but they would be impossible to play set to any other music, so it's okay. 
And then there are the games that simply get it right. The critically acclaimed RolandoEdge, a game that I've pretty much raved about on here before, is exactly the same story. Great original soundtrack, but no problem replacing it with your own mp3s. Aurora Feint, Sway, Adventure, all great games, fun for long stretches and short bursts alike, with wonderful sound effects and the ability to keep playing your own music while you play the game. has a fantastic original soundtrack, but it's more than happy to let you listen to your own tunes instead.
With OS 3.0 coming this summer - promising access to the iPod's media library within other apps - we can look forward to greater interaction between games and the user's existing music and photos (and hopefully a legit portable version of AudioSurf), so I ask you, iPod game developers, please, think twice before shutting off my tunes. If you have to interrupt Super Furry Animals, at least make the audio component an important part of the game.
Related Articles:
The 61FPS Review: Edge
Whatcha Playing: Feintly Familiar
Joe's Top 10 of 2008: AudioSurf
Ports That Need To Be Made: iTouchRez