While designed for speed and ease of use, the Blender interface can be daunting for new users. One of the reasons for this is that is is largely hotkey-driven. Once you have these keys ‘in your fingers’ you’ll be able to use Blender like a true 3D Ninja, but until then you’re in for a steep learning curve. Here’s a bit of documentation that may be of help.
The Map constists of two parts: one for the 3D View and Object Mode and one for Edit Mode. If you want to dig deeper, there are also the Hotkey Reference Pages.
This map is still for Blender 2.40. I have contacted the Blender DocBoard group but it seems like they haven’t had time to update it yet. They have assured me that changes should not be too large to make this map unusable, though.
Note: please don’t turn this post into a UI discussion. I’m preparing a post about that subject where you can write all you want and say ugly things if you are so inclined ;-)