I have a credit-card balance that I'm working at paying off. I have been lucky to find (or get sent) a 0% balance transfer offer. Since I know what inertia is like, I tend not to move the money easily before the 0% rate expires and the higher rate takes over, I look for offers that are 12 months long or longer. I also check the balance transfer fee--traditionally, it's 3% of the balance with a minimum of $5 to $50.
Remember that paying this fee is like carrying your balance for the year not at 0%, but at 3%! Look for balance transfer fees of $0. Also, some offers have balance transfer fees after the fact, but not for the opening.
What I've seen in my mail lately is that 0% APR offers with $0 fees are much rarer these days. I did sign up for the AT&T Universal card, which is administered through Citibank, but I had to search online for an offer like that. (And your credit needs to be good enough. I don't know what their cutoff is, but it's worth a try, right?)
I just opened an offer that says, "0% Fixed APR on Purchases until March 1, 2009 when you transfer a balance NOW!*" Read that carefully. You don't get the 0% rate on a transferred balance. You get it on purchases--only when you transfer a balance. So the balance sits there, accruing interest at 13.99% as a minimum, and your payments are ALL applied to the purchases--which are not carrying interest anyway! The fine print: This offer (WAMU Visa Platinum) actually only requires a $100 balance transfer, and doesn't charge a fee on the initial transfer (or any transfer in the first 90 days). So you could play this one by transferring only $100, paying it off, and then charging whatever you usually charge and paying the minimum, but putting the balance in an interest-bearing account. Not putting the balance somewhere is a sure way to screw yourself financially. (Think of the phrase "balloon payment.")
The bottom line is, as my friend Paula says, "Failure to read is not an excuse." Good luck, my friends.