CREATE YOUR OWN KEY-PAIR:

$ gpg --gen-key

and follow the instructions.
Let the key be valid for 1 year.

$ gpg --keyserver pgp.mit.edu --send-keys xxxxxxx

where xxxxxxx is the key ID number (the hex value)


Recommended : generate a revocation file immediately
With this file you can tell the key servers that this key should not be used anymore. Keep this file protected, since anyone with this key can revoke your key.

$ gpg --output revoke.asc --gen-revoke xxxxxxxx

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IMPORT A FRIENDS PUBLIC KEY:

look xxxxxxxx up on a pgp keyserver on the web.

$ gpg --keyserver pgp.mit.edu --recv-keys xxxxxxxx
$ gpg --sign-key xxxxxxxx

if you need to sign against a specific secret key, use:
$ gpg --default-key xx(yoursecretkeyID)xx --sign-key xx(keyIDtobesigned)xx

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REVOKE YOUR OWN KEY:

$ gpg --output revoke.asc --gen-revoke xxxxxxxx
$ gpg --import revoke.asc
$ gpg --keyserver pgp.mit.edu --send-keys xxxxxxxx

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