Does anyone know how long we get to keep the case email accounts if we synched them with the google aps? I graduated in May. Any expiration date on youremail23@case.edu?

This thread might be of some use, but is by no means an official source of information:

http://forum.case.edu/read/11/24528/24528#msg-24528

The official line is "as long as Case offers GoogleApps," which is guaranteed (officially) to be for the next 3 years. (Not officially: most likely a lot longer -- so you should be good.)