Sure thing, though you could've looked at Andreis article about it.. but it's quite easy really
1. Unwrap lowpoly model
2. place the lowpoly and the highpoly at the same place so the intersect
3. Press "0" On your keyboard to bring up your RTT menu, enable projection and fix up your projection cage
4. Click the Add button somewhere just below and choose normalmap
5. choose where you weant to save it, name, size etc.
6. make sure you got proper settings in the Render Options.. I prefer to use Hammerslay with the quality of 1 for global supersampling.. and catmull-rom as filter.
7. Bake your textures in the RTT dialouge
8. if red fields show up, you'll have to edit your cage, as it's most likely intersecting with your highpoly. Or, if you get black dots, try using another or no global supersampler at all.
Note that the render window appearing does not show your final normalmap, it's only a sort of preview, the real normalmap is saved at the target location. So if your image is pretty much just black while rendering/baking, it's cause of the lighting in your scene, this will however not efffect your normalmap
Hope that helps.. atleast my fingers got some exercise
Cheers!