Microsoft have not announced any plans to release a version of Access for
the Mac. Obviously, I can't say that it will never happen, but I don't
expect it to happen any time soon.
I don't have any Mac experience, but I understand there is a Terminal
Server-compatible Remote Desktop client for the Mac. So one possible
workaround might be to use Remote Desktop to give Mac users access (no pun)
to Access applications on a Terminal Server.