Due to the success of the AdWords Seminars program, we’ve recently added a third level which builds upon the two existing AdWords Seminar levels. To help our attendees find the right session(s) that will best meet their need, we’ve renamed the sessions as AdWords 101, 201, and 301. These new sessions will be held in various cities over the rest of 2008, including Houston, New York City area, Atlanta and Charlotte, NC in the upcoming months.

Currently there are three different levels of AdWords Seminars:
AdWords 101: Beginner
AdWords 201: Intermediate
AdWords 301: Advanced

Source: Adwords Blog