Cross-posted from another response to a similar question... hopefully the links will come along.

Good stuff from the Bicycle Federation of Wisconsin:
http://www.sfbike.org/?employers
http://www.bfw.org/articles/bikecommuting.php

And BFW's "Parking For Free" employer's guide and case studies:
http://www.bfw.org/projects/commute.pdf

From the Bicycle Coalition of Maine:
http://www.bikemaine.org/btwemployer.htm

And from BikeIowa:
http://www.bikeiowa.com/asp/bike/EmployerGuide.asp

Lots of good stuff from the San Francisco Transportation Management Association:
http://www.sacramento-tma.org/Bicycling.htm

Some facts and figures from Commuter Connections:
http://www.mwcog.org/commuter/Bdy-bike10.html

And from RoadBikeRider.com, this is one of the best little handbooks that's currently out there... I've had a copy for awhile (and use it heavily in the LAB Commuting course), but they were giving it away last week at least...
http://www.roadbikerider.com/bc_excerpt.htm