I was having an issue using Gmail’s new IMAP service in my Entourage client. I ended up finding these extremely well documented instructions on how to do this.
The only step I changed was to not change my Root folder to be “[Gmail]”. When I did this I did not see my gmail labels as IMAP folders, which is a pretty cool feature. Instead I went to the Advanced screen, and set my special folders to be the [Gmail]/folder variants, which provides me with the best of both worlds.
I am a happy chappy, my iphone, entourage and webmail accounts are all setup wonderfully now, and they are all synced. Life is good.