The best tutes to start with for scripting are snYpir's Friendly Intro to Code Snippets and Johan Gustafsson's Scripting Guide. If you want to see some very simple scripts in action get the Tutorial Mission.
For general Mission Editor and mission creation stuff, start with the Getting Started section of the Tutorials. You should be familiar with all of the tutorials there before venturing further afield. Included here is a lot of good stuff on triggers. Make sure you look at The Real Armstrong's switch trigger tute.
For sound and music, the usual starting point is Bloodmixer's Sound Tutorial.
Oh, and
Welcome to ofpec!