I finally found it on the bottom of this page on the official Bitcoin site, along with a few other stylish graphics:
http://bitcoin.org/en/bitcoin-for-press I suppose this still doesn't answer who originally made it, but it seems safe to assume that graphics on the Bitcoin.org site are safe for public use.
As the Bitcoin community, we really need to work on getting the word out there by using central symbols, logos, etc. Heck, I came up with some nice little neon coin icons the other day and was planning to post them on here. Who knows, maybe someone will like them.