The Google help page for Apple Mail 2.0 is a little out of date, but it seems to be working.
What prompted me to do this is that the Mail app is not accessing my mailbox anymore. It just started having problems after I did a lot of offline work on the plane home from Florida yesterday. Now I'm getting a message in mail saying that some of the things I did offline are being reset AND mail can't seem to connect to my mailbox.
I forward all my emails to GMail anyway, so this seems like a good solution.
I've noticed that GMail has been more reliable at receiving emails faster than they usually appear in my Apple Mail mailbox. It also seems to have a great spam filter.