Sorry, I mixed up \chapter* with \addchap (which is only available in scrbook, the book class of KOMA-Script).
For the space above a chapter, in KOMA-Script there is the command \chapterheadstartvskip. With other packages, you'd have to change \@makechapterhead, I guess.
For questions like these, I can recommend the usegroup comp.text.tex. Start by searching their archive (
http://groups.google.de/groups/searc...Acomp.text.tex), for example for the words "space before chapter. Before posting anything there (using a decent newsreader), please be aware the Usenet etiquette differs from forum rules. So read quite a bit before posting there. For instance, never post a question without a minimal working example.