Moxier Mail Beta is now available in the Android Market for T-Mobile G1 users and promises the first Exchange ActiveSync push email solution for Android users. Moxier Mail will allow you to compose, send and receive email on your Android handset and sync/send via Exchange server.
Currently you should be able to download the app for free, but now that the Android Market is able to accept payment for paid apps, it's unknown how long the app will be free. It is also unknown to what extent you can sync information - whether it's limited to email or if you can also browse contacts on Exchange and sync contacts and calendar entries. It certainly wouldn't hurt to head on over to the Android Market and check out this app for yourself.