Bibliography

Free

http://www.cplusplus.com

Explains well what most the features of the language do for beginners.

Not official in any way, despite the amazing URL and Google rank.

Is said to contain many errors, and that cppreference is superior.
http://en.cppreference.com/w/

Similar to cplusplus.com, but seems to have more info.

Wiki driven.

Attempts to document all the language and stdlibs.

Many behaviour examples.
Design and Evolution of C++ http://www.stroustrup.com/dne.html

Ultimate source for "Why is the language designed like that" questions.
http://www.parashift.com/c++-faq/index.html

C++ FAQ.

Deep and extensive tutorial.
http://herbsutter.com/gotw/

Herb Sutter Guru of the week.

Hard topics with simple examples.
http://yosefk.com/c++fqa/

Comments on the quirks of C++.

Fun and informative for those that know the language at intermediate level.
http://publib.boulder.ibm.com/infocenter/comphelp/v8v101/index.jsp

IBM implementation of C++.

Contains a few extension, but lots of well explained docs with many examples.

Contains clear examples and explanations on very specific subjects.

Horrible navigation and URLs.
http://www.agner.org/optimize/

Hardcore optimization tutorials for C++ and assembly.
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html

C++ specification official bug tracker.

http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list

List of books.