Check out this wiki page for all of the technical things:
https://en.bitcoin.it/wiki/Category:TechnicalAlso people may be able to help you on this forum as well as #bitcoin-dev on freenode.
Though ultimately it is best to look through the code. Unfortunately the satoshi client is quite difficult to follow. Getting a basic understanding before you do that is a good idea I think.
I also looked a little bit at bitcoinj but couldn't get far because it was very incomplete at the time I first looked. It appears to be much more complete now. There are other libraries you can look at.