Be careful - many cards now charge up to 3% to transfer balances. That's �30 every �1000. You may be better going for a credit card that does not charge the transfer fee but has a permanent fixed low interest rate for the life of the debt.
Don't rely on being able to change again in 6 months or a year - interest rates are probably going to rise, and it will be harder to get low rate credit card deals.
There is good advice here, including the best rates.
http://www.moneysavingexpert.com/cgi-bin/viewn ews.cgi?newsid1107182516,76509,