The Springdale Shuttle bus makes 9 stops in Springdale. The bus will take you into Zion National Park and drop you off at the visitor center where you transfer to the Zion Canyon shuttle. Most important they stop/pickup at the Bit and Spur. Best restaurant and bar in Springdale.
Here is the schedule: http://www.nps.gov/zion/planyourvisit/upload/ShuttleSchedule2012a.pdf
A couple of notes, the shuttles are free! Also, no pets are allowed on the shuttle bus.
Once you've arrived in Springdale you'll need to use the shuttle to get around the park. From April 1st until mid-Oct. the shuttle moves people thru the main canyon. Getting up early and parking at the Visitors Center is what I find to be best, this lot will be full by 10 AM.
I know there is shuttle parking in certain restaraunts, I'm just not sure which ones. It is a separate shuttle that runs thru Springdale, it lets you off at the IMAX and you need to walk into the park for the canyon shuttle.
The shuttles are free! We go into the canyon all Winter and could not believe the crowds the last two weeks. Parking lots throughout the park were full. Believe me the shuttle is a neccessity.
Even off-season, the parking area near the Zion National Park Visitor's Center can get crowded quickly. Consider parking in town and taking the shuttle as an alternative.