Not an easy task since you have to remove the Front Bumper Cover to get access to it. Once that's done, remove the electrical connectors, the screws and the Headlight Assembly.
See "Headlight" on page 52 of chapter 11 "Maintenance and Service" in your "OWNER'S MANUAL".....
The 2008 Subaru Outback is a gas-powered vehicle.
The 2008 Subaru Outback has a 5-speed manual.
The 2008 Subaru Outback has a flat 4 engine.
http://www.cars101.com/subaru/airfiltration.html#00-04legacy
The 2008 Subaru Outback is 15 ft. 9 in. (189 in.) long.
The 2008 Subaru Outback runs on regular unleaded.
The 2008 Subaru Outback's turning circle is 35.4 ft..
The height of the 2008 Subaru Outback is 5 ft. 3.2 in. (63.2 in.).
The 2008 Subaru Outback has single overhead cam (SOHC).
The curb weight of the 2008 Subaru Outback is 3350 lbs..
The 2008 Subaru Outback has 16 valves.