Just in time for the holidays, your monthly credit or debit card statement may contain a surprise. But don’t look for any sugarplums here, it’s most likely a proverbial lump of coal that you should be expecting.

Failure to read these statements and inserts carefully may very well result in you paying higher interest rates, being embarrassed by rejected charges or trying to ask forgiveness for multiple overdraft fees.

The Wall Street Journal has a great piece on the coming wave of charge account modifications that banks are pushing through while they still can.

New laws and government standards that go into effect in 2010 will require card issuers to give more notice of significant changes in card terms, limit some interest rate increases and require more detailed billing statements. However, you can expect banks to do nothing to make these disclosures easy for you as the customer, if the alternative is padding their fat profit margins.

Most aren’t waiting for 2010. Before these new regs go into effect, banks are moving quickly to jack up rates and cut credit lines. While they borrow from the government at basically no interest and mortgage rates are at historic lows, credit card rates have risen since last year. According to the Federal Reserve the average credit card interest rate is 13.71 percent, up from 11.88 percent in May of 2008. An estimated 58 million customers had their credit limits reduced between April 2008 and April 2009, according to Fair Isaac Corporation, which issues the FICO credit scores.

Speaking of the holidays, these changes in credit policy have forced a shift in spending patterns this year.

You’ll need to be on the lookout for pending changes in the terms and conditions of your card agreements and overdraft policies, and be prepared to go to battle with the companies to keep your rates low and fees reasonable. The first arrow in your quiver is still paying your bills on time, keeping a low rate of credit utilization and being willing (when all else fails) to take your business elsewhere.

It’s shocking how many companies are willing to bend over backwards for new credit worthy customers while letting their long-term clients leave due to this kind of mistreatment. But remember that a lot of new inquiries into your credit file will lower your credit score, which makes it difficult to really shop around.

Fighting to keep more of your money out of the hands of credit card companies and banks is only part of a good financial plan in 2010. Need more ideas of what you should be looking out for? Take a gander at this checklist from CBS MoneyWatch and get to work.