Today I was notified of an update to PDANet for Android. It now supports USB tethering on Macs. Previously, Mac tethering was supported only via Bluetooth, which is slow. When I tried Bluetooth tethering my download speeds were in the 350 kbps range. Via USB it's around 2 Mbps, quite an improvement.
I sent the developer an email requesting clarification on licensing. Depending on which machine I'm using I may need to tether either my MacBook Pro or Hobbit, my MSI Wind Netbook running Windows 7. I need to know if I need to buy one or two licenses, since a desktop client is required for USB tethering. I'll post an update when I have an answer.
In the meantime, if you have a smartphone and the need to use it as a cellular modem, PDANet is worth checking out.
I received the following reply from June Software regarding my desktop client licensing question:
As long as you have PdaNet on only one phone device, you can install it on as many computers as you like.
June Fabrics PDA Software Support