pc to phone calling

Can any one tell me which is the best and cheapest PC to phone call provider

I guess
net2phone ?

directory.google.com/Top/...net_Phone/

check this link.. you will find many. Most of them work well.

[m_arijit]

my experience with dialpad is good (if you have internet connection at home via cable lines..with dialup, performance is not so good though at times)