I just started a new job (after being fired the last day of my honeymoon from another company), and one of my tasks was to get people with iPhones the ability to sync with the Exchange server. IMAP and POP were already opened up, but those aren’t actually using Activesync abilities. I wanted push and not pull technology!

After working with Exchange 2007 for so long it takes a little time to get used to 2003 again. So bear with me.

Open up the Exchange System Manager
Under Global Settings, right click on Mobile Services and select Properties

Make sure that you select the bottom two check boxes.

Then, on your ISA server, you must create the rule to allow mobile outlook access to:
/*
You may already have something like /exchange/*, /owa/* etc, but you do need the entire directory to be allowed access.