I just received a court summons from a Consumer Creditor lawyer. The paper was taped onto my apartment door.
The summons says it is filed on Sept 11 2008.

I want to provide/file an answer with the court but the summons says I have 20 days after such service. Does this mean 20days after Sept 11? Or when I've received this summons?
Can the courts verify that I received this notice today oct 30?

I had the same thing happen to me. The date on the summons is usually much earlier than the actual "service date" which is when you received the summons.

The process server has to file paperwork with the court, so the court will know that you will served on Oct. 30th... although you may want to call the court clerk and just verify everything which is always a good idea.

This is a good article about how to respond to a credit card debt summons, here's the link: Served a Summons Or Credit Card Debt Lawsuit - Don't Call the Creditor! (http://ezinearticles.com/?Served-a-Summons-Or-Credit-Card-Debt-Lawsuit---Dont-Call-the-Creditor!&id=1613780)

It is suppose to be from service date. A process server fills out a form that shows where, and how the notice was served.

But I would verify with the court the date they show.