I ordered the mud/snow mats as an option when I got my
05 Forester XT.. They are rubber mats, with deep grooves in them,
about 1/2". The deep grooves catch all the snow when we go to the
mountains, and the sand and mud when it rains in the lowlands. They
lift out easily and clean with the hose.  They are available at the
dealership parts department. Available for all 4 seats. BTW,  they
don't show any wear after many miles of use.
This is copied from subaru.com
QUOTE:
2008 FORESTER 2.5 XT LIMITED       
Floor Mats, All Weather     $50       
Custom-fitted, heavy-gauge floor mats help protect your vehicle's
carpet from sand, dirt and moisture. Not intended for use over top of
carpeted floor mats
ENDQUOTE..
If  you go to the "build your own" page, and get to the "Step 3 -
Choose your accessories" area. they are about 1/2 way down. Click on
the line entry and a photo will show up.

Another option is to go to www.weathertech.com
and use the "shop by vehicle" option. The resulting page shows
deep groove mats similar to what the dealer offers.
What they have that's really nice are the "Floor liners". My friend
has these and they protect even better since they are custom fit to
protect the entire carpeted area of the floor pan. They actually fit
over the door sill so there is no chance of getting slush on the edges
of the carpet as you enter the vehicle.  Go over all the buttons on
the website to see exactly how they are made & fit.
Good luck.

Just a couple more shopping ideas. Sometimes ebay will have car
accessories. I got a cargo net (new) and a used cargo tray for one of my
Soobs there.
I have aslo had good pricing and shopping experiences at
www.subarugenuineparts.com (email Jamie if you have difficulty finding
what you want - she is www.subiegal.com and works there!)

Carl