Below is the recommended system requirements for the beta and a list of all the places you can download the client. And while you have it downloading, you might want to check out Medal of Honor Official Website for a little more info like the weapons and maps you'll be enjoying on October 4th.
Recommended System Requirements
Operating System: Windows Vista (SP2), Windows 7. Processor: QuadCore 2.0Ghz. Memory: 2GB RAM+. Video Card: A video card with 512MB of VRAM and one of the following chipsets: NVIDIA GeForce GTX260; ATI Raedeon 4870. HDD Space: 2GB. Soundcard: Soundcard with DirectX 10 compatibility. DirectX: DirectX 10. Disc Drive: 16X CD/DVD Drive.