Auto Insurance Documents

How do I notify my auto insurance company that I’m cancelling my policy?

I just switched from Progressive to Geico (and saved almost $1200 per year!) How and when do I notify Progressive that I’m cancelling my policy with them? (My coverage with Progressive ends March 4th, and my coverage with Geico starts on March 3rd). I’ve heard that I must notify Progressive in writing; does Geico provide some sort of form or document to give the old company or do I have to actually type out a letter to Progressive?
To “bundysmom”: if you don’t have an actual answer to the question, please don’t respond. The whole point of Yahoo! Answers is for people to be able to ask questions such as mine…if you don’t like the question, keep it movin’….please don’t waste your time or mine.

Call Progressive, inform them that you are switching insurance carriers, and they will probably ask you to send a copy (possibly by fax) to them. If you don’t they will contact the state DMV and say you don’t have insurance, which will then cause you to lose registration on your vehicle.