BoostPro Computing offers pre-compiled Boost library binaries for Windows here. This is the easiest way to install Boost on Windows, since compiling Boost source code can be quite painful. As of version 1.42.0, BoostPro only offers 32-bit binaries. It is important to note this since the BoostPro installer does not mention that it is 32-bit anywhere. Other 64-bit libraries and code compiled along with this Boost flavor will give strange linker errors like this:
Foobar.obj : error LNK2019: unresolved external symbol imp__gmpq_clear referenced in function "public: __thiscall CGAL::Gmpq_rep::~Gmpq_rep(void)"
If you have to stick to BoostPro, then you might be forced to switch your other libraries or code to 32-bit mode.