I just have my gmail forwarded to Mobile Me and I still get it instantly on my iphone.
Only thing is it doesnt do anything with the mail in my gmail inbox so every once in a while I'll log onto gmail and archive all mail.
Same, and it's not ideal. (You know you can automatically archive forwarded messages?)
Actually, I just set it up so Gmail forwards to Me, and Me forwards to Gmail.
Luckily it doensn't forward ad infinitum:
a message sent to Gmail is forwarded to Me, end of.
But a message sent to Me is forwarded to Gmail and then back to Me, so it appears twice in Me. Meh.
But since Gmail is my primary service, I'm fine with this, and I get all my emails in all my accounts giving me freedom to roam ^_^