Using Google Music can be very useful as it holds most of if not all of my music library on the web and I can play it through a web browser, application, or Android app. You can even play it via Bluetooth to your car stereo!
Google Music for iOS devices is currently only available as a web app, but there is an unofficial app called gMusic in iTunes that allow you to use Google Music natively on your iPhone. gMusic was primarily made for the iPhone and iPod Touch.
gMusic loads songs, albums, and playlists quickly and allows you to create playlists and add music to existing playlists in Google Music. You can also search your Google Music library. gMusic supports running in the background so you can continue using your device and listen to your Google Music library.
If you want to try it out, you can download the app from the App Store for $1.99 here
