Some European cities claim a 50% or higher percentage of workers who commute to work by bicycle. In the U.S. it is estimated at less than 1%.
Currently, some employers provide incentives for their employees to bike to work. However, it is more common to see incentives related to ride sharing or mass transit. A common complaint is that the incentives offered to bicyclists are too low to encourage those who drive to change to bicycling. There will always be people who enjoy commuting and do it by choice. However, to get people accustomed to driving to change may take some novel approaches.
While it may take time, it is great to see a change in this area, and the fact that employers are recognizing and encouraging bicycling is wonderful.
Those considering bicycling to work, and those who may need a little more incentive should read "Bike to Work." It can be found at http://www.biketoworkbook.com/ It includes a vast array of topics such as: "Why Cycle to Work"; "What Kind of Bike"; as well as bicycling maintainence, urban cycling tips, security, bicycle clothing, and many others.