[quote name='Aleman']That changed recently, you can now remove credit cards from your account easily on xbox.com.[/QUOTE]
How recent is recently? During the Summer of LIVE promotion (or whatever it was called), 1 month of LIVE was $1. Good deal. Right after that, I bought a year of LIVE with a subscription card. I tried to remove my CC information after 2 months, since that month I paid for was over.
I had to spend 45 minutes on the phone with MS and then it took them an additional two weeks to get it off.
This was all back in September, so take that for what you will. Good deal for me though, as since I waited the perfect amount of time, they had to end my LIVE subscription to remove my CC and then they gave me a 12 month code to use, so I got 15 months of live $51 bucks.