When I first began becoming interested in learning more about studio lighting than what I was already doing, I found studiolighting.net. Bill and Ed are the photographers behind this amazing resource for studio shooters.
StudioLighting.net is most likely known and popular for their great podcast Lightsource. This podcasts interviews really great and technically proficient photographers about their lighting, their diffusion choices and even their experiences with subjects, but it really does narrow down to their lighting. Lightsource is certainly the reason I keep going back to this site. Of course, you can subscribe to their podcast through itunes.
Other things StudioLighting.net has to offer are articles, book reviews, news, diy tutorials and much more. This site has been in existence for years and continues to be a source of help and inspiration for studio photographers everywhere. Definitely one of my favorite sites out there. Check it out!