I've searched and searched, but I can't find anything definitive on enhancing weapons. I have a player who wants his wizard to enhance his own weapons, and the weapons of the party as well as create wonderous items. He has the feats to do so, but what does it take to make a masterwork sword a +1 sword? I figure the spell is "magic weapon" but what is the cost to create? Is there any tables in any books that I've overlooked or failed to look in? Please help me out. Thanks.
Dungeon Masters Guide has tables and text indicating the amount of time, gold, and xp that magic item enhancement requires, as well as feats and spells that are prerequisites. All this stuff is also on the System Reference Document (SRD) online, if you don't have the DMG.
I suggest searching the Index of the DMG. But I'll be nice and report what the index of the DMG says under "creating Magic Items". See pages 282-288 of the DMG. The SRD covers this as well.