The following information is out of date.
First we need to get the OpenNIC key.
gpg --keyserver hkp://liberty.uber.geek --search opennic
Next we need to sign it. Follow the dialogue.
gpg --edit-key opennic
Now to share this newly signed key with everyone else upload it back to the keyserver.
gpg --keyserver hkp://liberty.uber.geek --send-keys 4D931D54
Make sure you also upload your key!
gpg --keyserver hkp://liberty.uber.geek --send-keys (replace here with your keyid)
Verify that you have successfully uploaded the key by checking this
Here is the OpenNIC key fingerprint (but please note that if this page has been compromised, the fingerprint below can be trivially modified):
6FF1 C506 D596 3DF8 A441 2148 8364 62E9 4D93 1D54