If you can afford it I would strongly recommend subbing to video learning site Lynda.com. On that site there are literally thousands of tutorial videos made by professionals many topics. As for lighting in particular there are quite a few lighting courses, the best ones on Lynda.com are by David Hobby aka The Strobist. The cost of subbing is $25 a month which isn't bad for the thousands of videos you get access to. I subbed to Lynda and leant about lighting with speedlites, how to shoot portraits and much more. I would like to state for the record that I am not affiliated with Lynda.com in anyway, just saying that for $25 for one month you can learn a hell of a lot from that site. It is well worth a look.