The prepaid cards from Costco or WalMart have good rates. If I'm remembering correctly, the Costco one (MCI prepaid card) is 2.9 cents per minute for domestic long distance. I also noticed that Costco is now carrying an international prepaid card with rates like 6 cents per minute to Italy as an example. There is a slight charge for using the cards with a payphone 20+ cents, but no charge with land lines.
TF