Resetting Tire Pressure Monitor.
 

Here is a site I ran accross that resets all BMW Tire Pressure Monitors. Since this seems to be a recurring problem i looked for a solution in addressing this.

http://www.brakeandfrontend.com/Article/80507/tpms_update_bmw_systems.aspx

This couldn't have come at a better time. Thanks for posting the link. I'm in the process of purchasing a winter setup and had worried about how to reset the system if I swapped out my winter setup with my summer setup on a fairly regular basis (Colorado weather!).