Video tutorial here.

Dell guide here.

Basically, undo the cover plate with the screws shown: alt text http://img138.imageshack.us/img138/3408/dell1.jpg

Undo the 5 screws to take out the thermal transfer thingy. The black end part (2) is a filter. It is tricky and mostly unnecessary to get to the fan itself. I've found that the compressed air is unnecessary as the filter does a great job of collecting stuff. I live with a hairy dog and removed lots of hair from the filter and found the fan blades fairly free. alt text http://img248.imageshack.us/img248/3776/dell2s.jpg

Video tutorial here.

Dell guide here.

Basically, undo the cover plate with the screws shown:

Undo the 5 screws to take out the thermal transfer thingy. The black end part (2) is a filter. It is tricky and mostly unnecessary to get to the fan itself. I've found that the compressed air is unnecessary as the filter does a great job of collecting stuff. I live with a hairy dog and removed lots of hair from the filter and found the fan blades fairly free.