Hello Alex,
There are many useful books on lighting. Search through our Read About It section for several tips. John Jackman's book is popular and is not bad for an inexpensive summary.

DV Creators has some pretty good instructional DVD's on the subject, too. They're a good value for getting started.

Bill Holshevnikoff has a very good FREE brochure on his Power of Lighting site. He produced the material for Arri, which includes a copy with many of their lighting kits.

But, in the end, experimentation and keen observation will be your best tutors. You already have some lighting instruments so you're well positioned for some "lessons".