Hello and welcome,
The best walk through I've found, (and I'm sure others will disagree), is to be found at
www.happysufer.com, under Baldurs Gate II-the spoiler, it then offer's you the choice of three walkthroughs. The first (by Dan Simpson I think) is by far the most comprehensive wlak-through I've seen.
A word of warning though, it tells you EVERYTHING, and can be addictive.
Hope this helps.