Have you thought about just using PDANet? Seems like the money on it would be quicker and easier to tether, and in my opinion is MUCH easier to use. Once installed you just simply click on the PDANet icon on the desktop or on the i730 and hit "Connect" and bam, you are tethered. No switching to USB Modem mode, and it still is syncing your items. It is just a thought to something a little easier.

http://www.pocketgear.com/software_detail.asp?id=20794

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-Michael
Need help setting up your i730/i830 or other WM2003/WM5 Phone, as well as the other hacks I have done, check out the MRailing Guides and Links