New credit card rules designed to protect consumers from being charged excessive fees and rates without warning were signed into law today by President Obama. While many of the changes in the The Credit Card Accountability Responsibility and Disclosure Act were already put into place by the Federal Reserve in December, those rules weren’t set to take effect until July 2010. The newly signed bill will require that some changes be made by mid-August of this year, with the rest of the changes being implemented next February.

Among the provisions of the new bill:

Interest rate increases – Issuers can generally only raise rates on existing credit card debt if consumers are more than 60 days in arrears. Also, interest rates cannot be raised during the first year of an account.

Penalty fees – Under most conditions, charging an over-the-limit fee will be banned.

Marketing to college students – Issuers won’t be able to extend credit to those under 21 without first verifying their ability to pay or getting their parents’ permission.

Other fees – Retroactive rate increases for customers in good standing will be banned on existing balances. Rate increases for new charges are not allowed without at least 45 days’ notice. In addition, “double cycle billing” and “universal default” are banned.

How payments are applied – If your card has balances at more than one interest rate, payments must be applied to the highest interest rate first.

Bill payment – Bills can be paid online or over the phone without incurring a processing fee. Credit card statements must be mailed out at least 21 days before they are due.