[jwn2]

I figured out a hack that works for me. Actually someone else suggested this, I think. I created a private network with my MacBook Pro and gave the iPhone an address in the network. This put them on the same subnet. Once both were in the same neighborhood they happily sync'd.

What I discovered at my office is that with my MBP and iPhone sitting within inches of each other, somehow the routers for our wireless LAN put them on different subnets. I still haven't figured that one out.