This weekend's sports on TV, radio TODAY AUTO RACING 1:30 p.m. -- NASCAR Busch Series BI-LO qualifying at Darlington, S.C., Speed Channel 3 p.m. -- NASCAR Nextel Cup Mountain Dew 500 qualifying at Darlington, S.C., Speed Channel 8 p.m. -- NASCAR Craftsman Trucks Darlington 200 at Darlington, S.C., Speed Channel PRO BASKETBALL 7:30 p.m. -- Celtics vs. Charlotte at the FleetCenter, FSN, WWZN (1510) 8 p.m. ...