This has happened to me THREE different times on THREE different computers (all of the infections took place on Deviant Art, as well, so be wary). If you are infected, be sure to report it to the site and they will do their best to take down the ads that infected you.
Unfortunately, anti-virus software like AGV and Avast! do not work on this particular type of spy-ware.
The first time I was infected (on my old Windows XP laptop with AGV software), I had to wipe the hard drive and reinstall it (and the computer was still never the same again, imho).
The second time, on my brother's computer (also Windows XP and AGV protected), my dad installed Spyware Doctor and that managed to get rid of it. The product isn't free, but it's the only thing I've found that's worked effectively.
The third time was on my dad's Windows 7 64-bit computer. It had a subscription to Norton Internet Security, but it was ineffective at detecting the virus. Thankfully, Windows 7 seems to be a tad more resilient. I was finally able to get rid of the spyware by deleting my account on the computer (which was the infected account, and apparently I had done it soon enough that the virus hadn't reached my father's administrative account).
I'd definitely suggest Spyware Doctor, or if you have Windows 7 and multiple accounts on the computer, deleting the infected account before it's too late!