composing means arranging the objects/structures in the image. This could be done by either moving things around physically, like often done in still lifes, and/or by choosing perspective, focal length and framing.
well, this was not a hard definition, but those would be the easiest words i could put it into.
[ame=http://www.amazon.com/Elements-Art-Richard-Pumphrey/dp/0137203764/ref=pd_bbs_sr_2/103-8495391-9259827?ie=UTF8&s=books&qid=1179966814&sr=1-2]one of the best books written on the subject (composition and all elements of art)[/ame]
[ame=http://www.amazon.com/Point-Plane-Dover-Books-History/dp/0486238083]another, but a difficult read.[/ame]