Где взять библиотеки boost под 64-битный проект?

64-bit support
Starting with version 8.0, Microsoft Visual Studio can generate binaries for 64-bit processor, both 64-bit flavours of x86 (codenamed AMD64/EM64T), and Itanium (codenamed IA64). In addition, compilers that are itself run in 64-bit mode, for better performance, are provided. The complete list of compiler configurations are as follows (we abbreviate AMD64/EM64T to just AMD64):

32-bit x86 host, 32-bit x86 target

32-bit x86 host, 64-bit AMD64 target

32-bit x86 host, 64-bit IA64 target

64-bit AMD64 host, 64-bit AMD64 target

64-bit IA64 host, 64-bit IA64 target

The 32-bit host compilers can be always used, even on 64-bit Windows. On the contrary, 64-bit host compilers require both 64-bit host processor and 64-bit Windows, but can be faster. By default, only 32-bit host, 32-bit target compiler is installed, and additional compilers need to be installed explicitly.

To use 64-bit compilation you should:

Configure you compiler as usual. If you provide a path to the compiler explicitly, provide the path to the 32-bit compiler. If you try to specify the path to any of 64-bit compilers, configuration will not work.

When compiling, use address-model=64, to generate AMD64 code.

To generate IA64 code, use architecture=ia64

The (AMD64 host, AMD64 target) compiler will be used automatically when you are generating AMD64 code and are running 64-bit Windows on AMD64. The (IA64 host, IA64 target) compiler will never be used, since nobody has an IA64 machine to test.

It is believed that AMD64 and EM64T targets are essentially compatible. The compiler options /favor:AMD64 and /favor:EM64T, which are accepted only by AMD64 targeting compilers, cause the generated code to be tuned to a specific flavor of 64-bit x86. Boost.Build will make use of those options depending on the value of theinstruction-set feature.

manking, для MSVS:
Подробнее здесь.