Can somebody steal my app idea?

I have published an Iphone app, and there's not yet an android equivelant of this app. Its gonna take me 3 months to create the android version, what if somebody creates an app just like mine in that time but gives it a different name? Can i cover myself?

It's possible that someone might steal your idea, but it's much more likely that someone will invent the same idea entirely independently. This happens all the time.

If you have a working app, it should NOT take you 3 months to create a second version. Look again at your plans and find out where your thinking has gone wrong. Get the droid version out the door in two weeks - that's the best protection.