The STL is an abbreviation of "Standard Template Library", which is a part of the C++ language. The STL, therefore, comes with any C++ compiler, including Visual C++. The STL is usually just distributed as a bunch of header files, since template classes must be completely defined in public header files.
Learning to USE the STL is a different matter entirely; almost ANY decent C++ book should cover it.
Also, you can search online for "STL tutorial" and I'm sure you'll get lots of hits.
Good luck!
Take care,
Nik
http://www.bigaction.org/