The House Creek Greenway is not quite finished yet, but it only lacks one bridge and about 100 feet of trail (as of July 8, 2012). This greenway therefore makes a nice ride if you don't mind turning around when you near the unfinished bridge. Alternatively, you can connect to the Reedy Creek greenway running between the NC Museum of Art and Meredith College by using an existing dirt trail.
The House Creek Greenway is about 3 miles long and starts across the street from the McDonald's at the corner of Blue Ridge Rd. and Crabtree Valley Ave. (This makes it easily accessible from the Crabtree Creek greenway).
Proceed down Blue Ridge Rd. a few hundred feet, then cross Blue Ridge Rd to the greenway proper. You will be heading uphill toward Glen Eden Pilot Park through a nicely landscaped area with several walking trails branching off either side of the greenway. After you pass through the back side of Glen Eden Pilot Park, you will find yourself on Glen Eden Dr.
Turn left onto the very wide sidewalk along Glen Eden, cross over the I-440 beltline and go approximately 200 feet. Make a U-turn to the left onto the greenway trail that parallels Glen Eden and then through the tunnel under Glen Eden. It seems like a convoluted way to design the greenway, but the nice thing about this approach is that you never have to interact with the traffic on Glen Eden Dr.
You will now be riding parallel to the beltline through a nicely forested section of greenway. You will then take a tunnel under Lake Boone Trail and cross Horton St. About one mile later you will arrive at the unfinished bridge.
Once the bridge is finished (perhaps August 2012 at the current pace?) and the last 100 feet of trail is paved, the House Creek Greenway will connect into the Reedy Creek greenway, at the Meredith side of the greenway/pedestrian bridge over the beltline. For now, if you want to get to the Reedy Creek Greenway, it is possible to walk your bike under the unfinished bridge or take the dirt trail under the power lines (which will be obvious when you see it) if you are so inclined.
Here are some photos of the House Greenway: