While deciding to buy an Android device rather than an iPhone might appear to be turning your back on the iPhone/iTunes ecosystem, iTunes offers a lot of appealing things that can tempt the Android user. From music to movies, from apps to the iTunes application itself, some Android users may want to use iTunes. The question is: when it comes to iTunes and Android, what works and what doesn't?
Playing iTunes Music on Android? Yes
Music and podcasts downloaded from iTunes are compatible with Android phones in most cases. Music purchased from iTunes is in the AAC format, which Android plays.
The one exception to this are songs bought from iTunes prior to the April 2009 introduction of iTunes Plus and the removal of DRM from iTunes songs. These files, called Protected AAC, won't work on Android because it doesn't support iTunes' DRM. However, you can upgrade these songs to Android-compatible Purchased AAC files for US$0.30/song.
Podcasts downloaded from iTunes are MP3s, which are compatible with Android.
Playing iTunes Videos on Android? No
All movies and TV shows rented or purchased from iTunes have digital rights management restrictions. Because Android doesn't support Apple's iTunes DRM, video from iTunes won't work on Android. Other kinds of video stored in an iTunes library, such as that shot on an iPhone are compatible with Android. That said, if you get software to strip out the iTunes DRM or that does that as part of converting an iTunes video file to another format, you should be able to come up with an Android-compatible file. The legality of some approaches/uses here is questionable, though.
Running iPhone Apps on Android? No
Alas, iPhone apps don't run on Android. With the huge library of compelling apps and games at the App Store, some Android users might wish they could use iPhone apps, but just like the Mac version of a program won't run on Windows, iOS apps can't run on Android.
Reading iBooks on Android? No
Reading ebooks purchased from Apple's iBookstore requires running the iBooks app. And because Android devices can't run iPhone apps, iBooks are a no-go on Android (unless, as with videos, you use software to remove the DRM from the iBooks file). Luckily there are a number of other great ebook apps that do work on Android, like Amazon's Kindle.
AirPlay Streaming From Android? Basically, Yes
Android devices can't stream media via Apple's AirPlay protocol out of the box, but with apps they can. If you're already using AirSync to sync your Android device and iTunes, a $5 upgrade will add AirPlay streaming. Another Android app, Twonky Mobile (free), also supports AirPlay.
Syncing iTunes and Android? Basically Yes
While iTunes won't sync media and other files to Android devices by default, with a little work and a third-party application, the two can talk to each other. Two apps that can sync iTunes and Android are doubleTwist from doubleTwist and TuneSync from High Wind Software.
To learn more about using doubleTwist for syncing, check out this video from About.com's Brent Rose.