The AMD OpenCL coding competition seems to be Windows 7 64bit only. So if you are on another version of Windows, OSX or (like me) on Linux, you are left behind. Of course StreamHPC supports software that just works anywhere (seriously, how hard is that nowadays?), so here are the instructions how to enter the competition when you work with Eclipse CDT. The reason why it only works with 64-bit Windows I don’t really get (but I understood it was a hint).
I focused on Linux, so it might not work with Windows XP or OSX rightaway. With little hacking, I’m sure you can change the instructions to work with i.e. Xcode or any other IDE which can import C++-projects with makefiles. Let me know if it works for you and what you changed.