Chances are that Apple won’t approve an app for Google Music as it would directly compete with their on iCloud offering. But the webversion works just fine, no flash, and all the music…
And if you’re wondering, login to Google was easy. Buffering took some time but I have a shitty wi-fi connection. After the load, play was uninterrupted. Worth noting, play continued in the background when I switched to other apps.
Update: I just noticed, you can start and stop the music with the remote of your headphones as well!