HackNDevJoining
Hack&Dev is a pretty loose community with almost no formal structure. This means the way to get involved is to just do something, whether by patching a misbehaving driver or program, writing documentation or even just reporting bugs. It's also a good idea to hang out in the IRC channel.
Coding
If you're a programmer and would like to help out, make a patch of your changes. If your patch is device specific, send it to the lead developer(s) of your particular device. Check the project page on the handhelds.org wiki to find out who they are if you are not sure. Contact Vladimir (Farcaller) or Alex for access to the appropriate respositories and other things.
Documentation
We're always in need of guides and other documentation. Don't bother asking anyones permission go right ahead and edit the wiki. That's what it's for!
Bug Reports
Use trac for this.