Where is the cabin air filter on a 2001 Subaru outback sport 2.2 engine?

This information with sketches is available in your owner's manual. If you don't have one Subaru thoughtfully supplies on in .pdf format here:

http://www.subaru.com/owners/resource-center/owners-manuals/search.html

I just looked up this information and it is all there. If your car is equipped with the optional filter it is under the dash on the passenger's side.