I've been waiting semi-patiently since last week for my Gmail account to be IMAP-enabled. I even tried setting up Apple Mail to use IMAP this evening without IMAP being an option on my Gmail settings (it didn't work even though someone claimed it worked for him).
But now suddenly, I have IMAP access for Gmail a mere 3 hours later! This is probably a coincidence, but if you are still waiting for IMAP, give it a try.