[Brian]

Rigel, OmniFocus can't sync over a USB connection to your phone, though we wouldn't complain if Apple made that possible at some point. :-)

The help article I mentioned walks you through setting up a WiFi connection directly between the Mac and the iPhone without any base stations or other devices on the network in the middle.

As bill mentioned, though, it requires a Mac with a built-in wireless; sorry I didn't make that clearer!