I entered the US in Feb.2002 and I was given 6 months (Aug.2002). I have made arrangements to go home end of Nov. 2002. What do I expect at the airport? I was told that technically you are given 120 days to leave after your "allowed length of stay" expires. Need advice.

I don't think you should have any problems leaving the country. If you experience any problems at all it will be when, and if, you attempt to re-enter.

The answer is simple.
You already overstayed, but total overstay will be less than 180 days, so no ban applies to you.

BUT
Your B-2 visa becomes void even after a 1 day overstay.
Before your next trip to the USA, you need to apply for a new visa.

Same holds for people entering under VWP
After a 1 day overstay, you can no longer enter under VWP, and Must get a visa.

From what I hear, it is not easy to get a visa after an overstay.

A side trip to Mexico, Canada, the Bahamas or wherever before you ovestayed, would have been a lot wiser!
If you planned to come back soon, after your second entry from the side trip, then you could have problems. But if you had no plans for a trip within the next 1-2 years, you would have been OK.

Another side to your overstay, you are tax liable for your income (US or abroad), if you stay more than 6 months in the US!

nothing will happened in the airport when you are going back. but if you want to come back TO US then it will be very difficult.