Perhaps there's another way, but I only know of outlook sync of local email via itunes (as in: connect the iphone to itunes via a usb cable -- there's no push email). As far as I know, there's no push of non- @me.com outlook email. If you want push email, it has to be done via a @me.com email address (well, with MobileMe -- if you get service from another, probably more expensive exchange provider, you can get push of that exchange-based email).
Now, if you use a @me.com address, you can read/write @me.com email from outlook, but any "push" is occurring via @me.com's servers, and not outlook.