Grab, Alison's advice is good.With regards to the other parts of your question, I can't get above a 28.8K connection at the moment and am having no sound problems although my PC is quite a bit faster than their miminum spec.
There have been a number of people having initial sound problems but as far as I am aware, everyone who has persevered with the audio settings (which PalHelp will guide you through) has managed to get reasonable sound.
I say everyone but I seem to remember Susan of DT having problems that required an upgrade but IF my memory serves me correctly, she was running a machine that was below the minimum spec ?14.4K modem?
Jon