If your keyring is already unlocked, all you have to do is:
So you won't be prompted for your passphrase a whole bunch of times...
sudo aptitude install gnupg-agent pinentry-gtk2 pinentry-curses
replace 0xD34DB33F with your GPG Key ID
killall -q gpg-agent
eval $(gpg-agent --daemon)
export DEBFULLNAME="Your full name as it appears on the GPG key"
I can attest to the second part. The first part is a copy-paste, but it seems legitimate. I would think you would still have to unlock the key once, but it would stay unlocked.