For what it is worth, my Droid will not connect thru wifi (Airport) sharing ("Internet sharing" from Sharing System Preference). I have a Mac in my office, and every other device can get on the internet using Airport wifi sharing, except my droid (including iPhone, other macs, windows PCs). The droid says that it is connected, but it can't access any sites. I can't figure out how to debug the problem.
I solved it by finding an unused airport, and plugging it in. The droid has no problem connecting thru an apple airport device.
I have tried rebooting the mac, and the droid, many times.