1. Because I was bored for a few weeks
2. I used GCC/MinGW to compile it. Code::Blocks was used for development, so if you have it you can use the wxBots.cbp project file. There are also Makefiles in the source zip, Makefile is my UNIX-like-system makefile while Makefile.mingw32 is for the Windows build - MSYS is probably necessary to get a working make (you probably need to edit CXX/LD/CXXFLAGS/LDFLAGS, standing for (C++) compiler, linker, compiler flags, linker flags respectively to fit your own paths). I would have used MSVC++ but (1) it uses 1.1GB of disk space and my VirtualBox-emulated Windows machine only has 5 GB total, (2) GCC is the native compiler on my development machine (running Linux). It should not be too hard to get it to work with MSVC though.
Oh, I forgot to mention that because it uses wxWidgets for GUI, it should work on most 32-bit platforms which wxWidgets supports.