Hey guys, if you want to know so badly, preorder it. It's not fully optimized for low-end computers yet, but that should give you some idea of whether or not you can run it.
As a general guideline, I'd say (and this may be totally inaccurate) that you'd need at least a 1.8Ghz processor (perhaps something close, ie, 1.5, would work too), 512mb-1gig of RAM, and a decent video card (NVidia or ATI; some newer integrated graphics cards would work too)
To check your exact specs on Windows, go to Run and enter "dxdiag", without the quotation marks. The most common issues I usually see with people trying to run games are their video cards or their drivers; always make sure to have the newest drivers installed on your computer, your video card should at least support Vertex and Pixel shaders and have DirectX 9. Don't freak out if you don't meet my "minimum requirements"- they might be completely overestimated. Be a little patient. If you don't plan on pre-ordering, then you don't need to know about the requirements until the release anyways, right?