UPDATE: We're getting really scattered reports, but it looks like the site has a new look/feel, a new $99 developer option for Mac (to match the $99 iPhone option), and...? Let us know if you see anything else.
Also, some developers have told us that their registration no longer works after the update, so there may be some bugs at work. Let us know if you're having any problems
It's not the Apple Store, but 9to5Mac is reporting that Apple's iPhone SDK developer portal, developer.apple.com is down: