That’s what libgdx was meant for: port your stuff from the desktop to Android easily. The first framework to join the party is Slick by Kevin Glass, a pretty famous Java OpenGL based 2D game engine. Of course the poor thing has still some rough edges like temporary object allocation and so on, but Kev was able to port one of his games already, running pretty well:
You can find a preliminary apk at http://dl.dropbox.com/u/1668516/android/Slick-Android-Test.apk. Make sure to report any bugs in this JGO thread.