First, determine if the noise is inside the opener or in the door hardware. If it's in the opener, you can dig into it if you have some confidence in that area.
Chances are, it's in the door hardware. Start by oiling (not greasing) every roller on both sides of the door, including the shaft that each roller is connected to, and oil every hinge on the body of the door. Also oil the chain - I think motorcycle chain lubricant is a good way to go for the chain. Then GREASE the bar that the door carrier pulley slides on.
After all that, disconnect the door from the unit and manually operate it to see if there are any binds.
Many openers have adjustments for UP and DOWN power. You might need to make an adjustment. Hopefully, you still have the owners manual.
[This message has been edited by rpxlpx (edited September 13, 2001).]