Here are some great sites to go to improve your skills and for inspiration!

Tons of techniques with instructions - from lighting to workflow. A bit more equipment specific but there's no beating the wealth of very helpful information here.

The sub-heading on this website says: Learn how to light. Enough said.

Sublime Light
Not just great techniques on lighting but there are also some good techniques on general shooting as well. You can also get some reviews on gear as well.

To get the most out of this website you're going to have to create a login account but it's free. Loads of hints, tips and discussions on just about any topic concerning photography.

Weekly Photo Tips
This site is for inspiration and some helpful tips on setting up your shoot, complete with diagrams! Also photo contests for you to enter and gear reviews.

Digital Photography School
Tips, tutorials, reviews, post production, contests, the works. Get it all here.

Photoshop Tutorials and Adobe Photoshop Killertips
These two aren't exactly about cameras and shooting, but they're every bit as useful for your post-production workflow using that ever-popular software. PT shows you detailed instructions on how you can manipulate or enhance your pics, while APK does this through short videos that you can download. Take your pick.