Ok, let me get to the specs first.
Ubuntu 10.4, Sound card works great when recording and doing playback with Ubuntu. Skype v. 2.1 beta.
In Windows XP, same system, I dual boot. When I use Skype (latest), and I try to call to a landline in the US, everything works fine. Everyone can hear me fine and there's no problems.
The problem: When I use Ubuntu, and Skype, there's crackling, dropped off sound, and the overall quality is bad.
EDIT: The biggest issue here is dropping parts of the call. Why does it do that?