I am still putzing around with my Android client work....but as for [mike]'s Java code, I'd think storing the block headers in an SQLite database may be the way to go, but you'd need to edit that code to do so as I saw it.

But great job on the first pass. I should clean up and release what I have with respect to using C2DM to notify a bitcoin client that blocks are waiting. Also, now that we have a growing DNS spec...I don't feel bad if I am not part of the network as a whole.