I am going to be a smart ass about this, since you were not very specific: Try a saws-all or rotary grinder.... :chairfight:
Since I really don't think that is what you are trying to do (did I say you were not specific??) and really just want to remove the molding along the A-piller......... you first have to remove your sun visor. After you unscrew and remove the sun visor, the upper window molding (not sure what else to call it) will be loose enough to extract the A-piller molding. The A-piller molding just sits into a slot in the dash and is not clipped to it. If you know which end of a screw driver to use, it should take you all of about eight (8) minutes.
