I followed all of the tutorials, and by all accounts everything should've been working fine—even OSX itself said it had an IP and was on the internet. However, everytime I went to actually get onto the internet I would get errors telling me the server wasn't there.
After banging my head over the problem I saw a post on the PearPC forum with the solution! ZoneAlarm was screwing everything up. Not being able to tell the network requests were coming from a single program, ZoneAlarm did the only thing it knew how to do with unknown requests: it blocked them.
Once ZA was turned off I was on the internet instantly. Since I use ZA as my firewall this solution is unacceptable, but at least I know why it wasn't working before. Hopefully more information on configuring a proxy to get around ZA will be offered.