the following link is so far the best tutorial on standard library and stl i've ever found. it's from microsoft though, so i do not guarantee everything introduced will work with all compilers.
there are some exciting improvements for VS 2010 mentioned in tutorial. one of my favorite is the lambda expression.
Key in "STL tutorial" in Google search and you will get a few hits. But some of them tend to focus only on certain specifics in STL. I learn about iterator tags and functors and mem_fun, mem_fun_ref etc in some other places.
Long long time ago I did came across a STL tutorial from a Masters student doing his PhD on C++ STL but I lost that copy. It is very comprehensive and last I check the link is not there anymore. I guess he finally get his PhD and take down that site subsequently ? :P