Mozzer
I had two credit card accounts on the go, but only one credit card (I keep the UB cc at home and I cut up the MBNA one and closed the account- I was charged the €40 at the beginning of the year, I'm hoping that's it, but from reading some of the posts here it seems that I might be charged for next year as well - on the closed account that is).
I think the main thing is to cut up the card with the interest immediately. It was a wrench because my credit limit with MBNA was about three times what UB were giving me - I know my nature and it would have been too much of a lure having cleared it and having all that credit available. I have to say that reading the boards here had given me the incentive to start on the road to reducing my debt.
It is hard for the first while because you are paying two payments, and I found that UB's miniumum is far more realistic than MBNA's (sometimes they were looking for so little that it was great, but the interest would keep piling on).
Well that's my experience for what its worth. Good luck!