Mndrix and I (and a couple other discussants) have developed an exportable GPG identity protocol. http://wiki.bitcoin-otc.com/wiki/GPG_Identity_Protocol
Quick summary: "This page outlines the protocol for exporting your GPG identity to other sites which may or may not support GPG authentication directly. The basic idea is that you can post a GPG-signed message to some area of your user account on the site, connecting your site id with your key via the signature, and then others can verify your signature and be certain that you are the same person on multiple sites.
Please check it out - your feedback (please post in this thread) would be appreciated.
In the future, I will be putting in the code on #bitcoin-otc to automagically query people's identities and ratings in various communities based on their OTC GPG auth, mndrix may implement it for coinpal, and hopefully other sites in the bitcoin community can join in so that we can create a broader web of trust.