I’ve heard a few good things about Skype recently so I downloaded a copy for my PowerBook. Very nicely designed UI but with a lack of willing and capable participant on the other end of the connection I haven’t been able to test out the actual speaking part yet.
The last time I tried VoIP was when I was working in Portland and Leah and I talked over the net using iChat. Pretty good quality but with a slight time delay. Perhaps Skype will be better, especially with its cross-platform nature (i.e. more potential users)?