I imagine if there was one available it would just be called weightwatchers as it is in the app store-although I don't really know how Android phones work
There are various apps for Android. There is an official WW which is just a calculator and very slow. There are other apps which better. Search the Android market. Sadly there isn't one like the iPhone which links to esource. There's an app called WW points which has a tracker and various bits and bobs but it doesn't link up.
There is a official ww iPhone one, I use it and find it great.
If your a WW online user is logs into your tracker and all.
It's only on the Uk iTunes, not the Irish one.