combined:
tar -cvzf - sourcefolder | gpg -c > zipfile.tar.gz.gpg
with password:
tar -cvzf - sourcefolder | gpg -c --batch --passphrase yourpassword >zipfile.tar.gz.gpg
tar -cvzf - sourcefolder | gpg -c > zipfile.tar.gz.gpg
tar -cvzf - sourcefolder | gpg -c --batch --passphrase yourpassword >zipfile.tar.gz.gpg