First of all, this does not effect iTunes customer accountsthis is a different system and all iTunes customer information is completely safe, Apple told me.
Its also important to note that the hacker did not get access to any app code or even the servers where the app information was stored. The hacker also did not get access to any credit card information.
The only thing that the hacker could have gotten access to was the names, email addresses and mailing addresses of the developers. At this point, Apple doesnt know if the hacker even managed to see that information. Worse case, that is all the information they would have seen, according to Apple.