As part of the development of Agit I created this patch of ConnectBot which allows other android apps to use it as an ssh-agent. This means that Agit doesn't need to actually manage or even store SSH keys itself, which is pretty cool.
You only need to trust one app with your SSH keys - that's ConnectBot, which already has great infrastructure for managing public keys - and all other apps defer to it for signing the cryptographic-challenges required to initiate an SSH session.
The pull-request to get this functionality merged back into ConnectBot is here:
See the Agit SSH page for more details: