I had written a nipsy little ditty entitled GPL Icon Frenzy but in the maelstrom that surrounds any site relaunch, it was lost in the ether of ZDNet's servers, probably forever, upon the launch of the New & Vastly Slicker ZDNetUK.
So, just in case you had the hunger for yet more GPL icons, here are those links again:
Crystal icons, as made by Everaldo, all Free in the best sense of the word. (Funnily enough, I've been using the 16x16 pixel icons in Evolution to help me with my Getting Things Done experiment).
And Tango icons (again), totally lickable iconsets.
There we go.