If you're an Android fan who likes the iPhone hardware you're in luck. Android has been ported to run on the iPhone. Just check out this YouTube video posted by
planetbeing. He has apparently ported a debug version of Android to the iPhone, complete with drivers.

As you can see in the video the Android port is a bit buggy, but I'm sure they'll work out those kinks.

The iPhone does fairly well with Android, but it's not the fastest phone to run Android. You'll probably have better luck just picking up a Nexus One or Droid Incredible.