Mike, sounds like your roof is flat! If the ends of the 2x4 joist in the ceiling are depending on this wall you want to remove to hold them up, then they are load bearing--cause the wall is holding that end up...if the 2x4 joist run across the wall you want to remove then that wall is keeping the ceiling and 2x4's from sagging. either case, if you want to remove the wall it needs to be replaced with a solid, strong beam made of two 2x10's or bigger with a half inch piece of ply wood sandwiched in between to make it stiff to span across those 2x4's. This beam should be supported with Jack Studs ( 2 or more 2x4's nailed together to form a strong post) on each end--you might want to hire this one out if it sounds too complicated! Hope this helps..and good luck!