C++ FAQ Celebrating Twenty-One Years of the C++ FAQ!!!
(Click here for a personal note from Marshall Cline.)
Section 37:
[37.2] Where can I get a copy of "STL"?

Since the classes that were part of the STL have become part of the standard library, your compiler should provide these classes. If your compiler doesn't include these standard classes, either get an updated version of your compiler or download a copy of the STL classes from one of the following:

STL hacks for GCC-2.6.3 are part of the GNU libg++ package or later (and they may be in an earlier version as well). Thanks to Mike Lindner.

Also you may as well get used to some people using "STL" to include the standard string header, "<string>", and others objecting to that usage.