License Driver in US
There is a basic overview of this process for foreign people at the following link on the Internations (it is required to create a free account there) - http://www.internations.org/guide/usa/16277-transport-driving/getting-a-us-driving-license-16257?ah01_enabled
You can get your license at any office of the MO-DOT (Missouri Departament of Transportation). You will require some documentation (http://dor.mo.gov/drivers/idrequirements.php). The close MO-DOT office location can be found at http://dor.mo.gov/offloc/.
US Citizenship & Immigration Services - Citizenship Resource Center