I'm looking for a website (hopefully independent of major card issuers) that has a good list and comparisons of credit card interest rates for the United States as well as historical data showing how often they change (raise) their rates.
Many places. I usually look at these two:
CreditCards.com and BankRate.com. They conduct surveys and you can find some historical information, but let me reiterate: the rates are set and changed per card-holder based on the card-holder's history. Also, because of the CARD Act changes, the historical trends and patterns will not necessarily be relevant any more. The new law limits the rates and how they can be changed, and the historical data does not reflect the new rules.