Let the hive mind of Engadget get that for you.
"I've found myself using my PC for a lot of conversations lately, and I'm also considering recording a podcast to share with anyone who will listen. There are tons of USB headset / microphones out there, and I'm hoping someone has some solid recommendations based on experience. I'll consider both headsets and standalone mics, by the way, but I'd like to keep the bill under $100 if possible. Help!"
A great idea, but as a Canadian I've seen several systems like it come and go.
Mondex existed a decade ago and was a stelar system - you could load it up at a bank machine, or even at a payphone via the payphones built in card reader.
More recently, Bell Canada has a system in play called Dexit - unfortunately based on personal experience, the terminals at the retailers rarely work..if you actually find a retailer that supports it to begin with.
This system seems doomed to fail as well since it limited to supported cellphones.
Really, give us a keyfob or a chip embedded card...and then actually get retailers and banks onboard, and it'll work.