Anyone tried FWD (free world dialup) yet? One advantage over skype is it is based on SIP instead of P2P technology. So connection to other SIP phones is possible. There is beta testing of FWD to packet8 VoIP going on now. Lets say you use the packet8 at home for VoIP and load FWD on your PDA, you can call home (or any other packet8 phone) from any wifi connection.
I have been reading that there is a lot of PSTN access numbers popping up in the US for dialing into SIP or FWD phones from a landline. Michigan seem to have the most at this time. See following links for info.

http://www.fwd.pulver.com/support/faq/general#330


http://sipphone.com/access/

http://www.packet8.net/support/faqs/...33&Keyword=fwd