Read the fine print carefully. Some cards, especially Providian, offer 0% until the summer of 2007 if you make a balance transfer. However the 0% is only on purchases made during that period. The balance transfer interest is around 7%. I've been taking advantage of these offers for years and yet this one fooled me.
In recent months, due to the current high interest rates, there have been far fewer offers with a low max fee; usually it was between $50. and $75..Now there is generally a 2% or 3% upfront fee on the whole amount borrowed. I always call and ask if they can give me a better rate. Sometimes they offer 0.9% or 1.9%.
Keep in mind too that new rules allow them to bump a low rate up to an exorbitant rate, like 21%, if you are late making a payment on ANY credit card or bill, even if it has nothing to do with their company.
I made a good profit in the stock market over the past 3 years using all that "free" money. The offers still pour in every week but the terms are no longer worthwhile.
By the way, you can usually write one of the checks to yourself and deposit into your bank account instead of using it to directly pay off another loan. Many companies will wire the funds into your account at no extra charge. I have read articles stating that this is a better way to go. If you send a balance transfer check to pay off the balance on another credit card, the info is supposedly entered into the system in such a way that it lowers your FICO score and discourages other cretit card companies from offering you good balance transfer deals. They say that it is better to have the funds from the present offer deposited into your bank account and then pay off the other company with your own personal check.