From ArborWiki

Airport transporation by bus from DTW to Ann Arbor ($10 special, $15 regular), Jackson ($20) and Lansing ($25), 8 trips per day.

Stops in Ann Arbor starting October 1, with connecting service to AATA Route 36. Buses leave Ann Arbor at the Four Points by Sheraton hotel for the airport at 4:30am, 7:00am, 8:30am, 10:00am, 11:00am, 12:01pm, 2:00pm, 3:00pm, 4:00pm, 5:00pm and 7:00pm, arriving the McNamara terminal 30-35 minutes later and the Smith terminal 35-40 minutes later.

http://www.michiganflyer.com

In the news:

• Buses to run from Ann Arbor to Detroit airport, Michigan Daily, Sept 19 2007
• Company eases trip from E.L. to Ann Arbor, State News, Sept 19 2007
• Ann Arbor to Metro bus service, Arbor Update, Sept 14 2007
• Shuttle to offer rides to Metro Airport, Ann Arbor News, Sept 15 2007