This is probably a great place to get a newby enthused. There are tons of trails, none of them threatening. There are a few snippets of good singletrack, but they are too short to really give this place a high recommendation. It's easily accessible, which means also very busy with hikers, dog walkers, and equestrians. If you get too creative looking for better lines, you're liable to end up dead-ending into private property.
Head south of Missoula on Brooks (aka hwy 93). 1.2 mi after crossing the Bitterroot River, go right on Blue Mountain Road. When the road goes right, veer left and follow to the trailhead.
http://www.singletracks.com/item.php?c=1&i=2456