A little more info from TC: http://techcrunch.com/2013/07/21/apple-confirms-that-the-dev...

Update — Just got off the phone with an Apple rep, who confirmed a bit more:

- The hack only affected developer accounts; standard iTunes accounts were not compromised

- Credit card data was not compromised

- They waited three days to alert developers because they were trying to figure out exactly what data was exposed

- There is no time table yet for when the Dev Center will return