Factory service manuals are available for less than $10 on eBay. They are a .pdf format download so you can have it ready for use shortly after purchase.
check owners manual, it will be in there
In The Subaru Legacy(Outback) Service Manual and the Chilton or Haynes Repair Manual for the Legacy & Forester 2000 thru 2006.
Service manuals for the Legacy Outback on CD are available on eBay for less than $10. I checked the one for my 2007 and it includes the diagram that you seek.
In the "Supplement for 6 Cylinder Engine Model" of the 2001 Legacy Service Manual, under Mechanical - "V" Belt..... Or take a picture before you remove the belt !!!!!
Subaru Outback was created in 1995.
The Subaru Outback is sold in the US.
A Google search turned up a hand full of diagrams. https://www.google.com/#q=2001+subaru+outback+3.0+serpentine+belt+diagram
Read the first answer here:Where_can_you_find_a_1993_Subaru_Legacy_engine_diagramThere are Haynes and\or Chiltons guide for every Subaru Legacy\Outback to 2005(US Models) you can find the specific one you need on www.haynes.com they have engine and body diagrams.
The 2006 Subaru Outback has 16 valves.
The 2013 Subaru Outback has 16 valves.
The 2002 Subaru Outback has 16 valves.
The 2001 Subaru Outback has 16 valves.