Although the Neverwinter Nights 1 Scripting Compendium was compiled by me a while ago, you may still find some of the tutorials here useful. (The materials was taken mainly from the Celowin's Tutorials and other tutorials from Bioware's Forum. I don't claim authorship, except copying them from the forum and re-formatted the materials into a "booklet" for my students easy reference.)
Free for personal and non-commercial use, no commercial reproduction please.
An important piece of scripting reference you will find invaluable is the Neverwinter Nights Lexicon. You can either use the Lexicon as a Website, or (better still) download the Lexicon's Help File from NWVault and use it offline as a desktop reference.
The [Neverwinter Nights 2 Lexicon] is supposedly under development by the same team (who made NWN1 Lexicon), unfortunately the site is currently under lock down. There is no telling when it will be ready for use, so you may want to check back at a later time.