The Midwest League playoffs begin Wednesday night with West Division first half champions, the WIsconsin TimberRattlers opening against the Burlington Bees in Burlington, Iowa.   The opening round is a best of three series with game two Thursday night at Time Warner Cable Field at Fox Cities Stadium at 6:35 PM.   If game three is neccessary, it will be Friday night in Grand Chute.   Clinton and Beloit meet in the other Division semifinal series.   East Division matchups have Lake County facing Bowling Green and Lansing taking on Fort Wayne.