What versions of a paper do I still hold rights to?
After accepting the article, the journal will ask you to sign a copyright transfer.  This document should describe in detail what rights the publisher gets, and what rights you retain.  If it isn't acceptable to you, you can try to negotiate; your institution may have an intellectual property office that could help. If all else fails, you can withdraw the paper and submit it to a journal with different policies (perhaps even an open access journal).

It is pretty common for the author to retain the right to distribute preprints.  

Congratulations on your paper!