I created them yesterday, but both mysql.*.com were both working simultaneously at one point. About 30 minutes after both got set up, everything went down. I sent in a support request, so for now I'm just waiting to hear back from them.
I'm not sure if it's a related issue, but at one point all my domains went down (5 of them) and then no phpmyadmin has worked since.
Not really a big deal for me, since I'm a casual user just wanting to play around with blogs. Hopefully other people with more important sites will get their sites up before mine.