Mastercoin pays its developers using currency created in the first block, in a system of bounties managed by the Mastercoin foundation. You can contribute a patch and get paid. Go read on their website, it's interesting.
Why the next? ;) We're definitely thinking about this. One dream I have is to move Open Source out of the "Tragedy of the Commons" example list.
Is it possible to help on this?
Yes, all that will be open source. Sign up on the Filecoin mailing list to keep in touch.