Below you can find links to some sites I like, grouped by category.
Modified March 28, 2013
7-zip: Free compression tool for Windows.
Git: Free, state of the art distributed version control system.
Visual Studio Express 2012 for Windows Desktop: Free, state of the art IDE and compilers for Windows development. Includes support for native C++11 applications and .NET desktop applications using C# and VB.NET (supports WPF).
Visual Studio Express 2012 for Windows 8: Free, state of the art IDE and compilers for development of Windows Store applications. Includes support for native C++11, Direct3D and .NET applications for the Windows Store (supports the Windows 8 native XAML library).
Visual Studio Express 2012 products home: Includes links for downloading all the Visual Studio Express tools.
Paint.NET: Free image and photo editing software for computers that run Windows.
Pro Git book: Excellent book about the Git distributed version control system. The digital version of this book is available for free, but you can also buy a printed copy from Amazon.
STITZ ZEAGER OPEN SOURCE MATHEMATICS
Stitz Zeager Open Source Mathematics: Free books about Precalculus, College Algebra and College Trigonometry.
Elementary Linear Algebra (Lecture Notes by Keith Matthews, 1991)
C++
isocpp.org: News, status and discussion about Standard C++.
Bjarne Stroustrup's homepage: This is the personal website of Bjarne Stroustrup, the Creator of C++, with lots of resources available.
Sutter's Mill: Herb Sutter on software, hardware and concurrency.
Thiago Adams website: C++ code samples.
Poco C++ Libraries: Modern, powerful open source C++ class libraries and frameworks.
Boost C++ Libraries: Free peer-reviewed portable C++ source libraries.
LLVM Compiler Infrastructure: A collection of modular and reusable compiler and toolchain technologies
Clang: A C, C++, Objective C and Objective C++ front-end for the LLVM compiler
Ceph: Distributed storage system designed for excellent performance, reliability and scalability.