i belive that both imdb.com and the parsing of such data is 'hardcoded' into xbmc. i suppose you could change this on your own, but it would take a lot of coding (not just the url, the parsing routines would take a lot of work). all of the source is in cvs on sourceforge if you are determined enough
read the xbmc online-manual, faq and search the forums before posting! do not e-mail the xbmc-team asking for support!
read/follow the forum rules! note! team-xbmc never have and never will host or distribute ms-xdk binaries/executables!