I had a credit card a while back that I stopped paying a while back due to being out of work. On my credit report it shows the original lender (WAMU, now Chase) and the credit limit, and that the balance was transferred or claim purchased.

But there is also an entry from Asset Acceptance Corp., for the WAMU account, for an amount nearly twice the original balance, and that amount has gone up since the last report I saw in '08. It seems that the collections group is adding interest to the balance?

Can I do anything about this?

You can always challenge the legitimacy (aka dispute). First start with the bureaus then request proof of debt ownership from the company reporting to the bureaus. You don't have to pay anything to anyone who doesn't have proof that you owe them. Good luck!