Hi Jora, I have used a number of products and methods to remove/reduce the appearance of beard shadow.
Firstly, without close shaving no cosmetic product will work very well....
In terms of shaving, we all have different levels of beard growth. I found that wet shaving was the best solutiion for me. The routine I developed was as follows with a twin or triple balde safety razor:-
1) Apply shaving cream and shave normally down your face with the hair growth
2) Wash off and scrub with a fine skin exfoliator (the anti-spot cleansing type with small beads is best). This prepares the skin and helps stop nicks and cuts.
3) You can either leave the exfiloator on, or re-apply shaving foam as you preffer
3) Carefully (and I mean carefully), with short upward strokes, shave up the face against the hair growth with light downward pressure on the razor. Initially you may get some redness, but with practice this will go away and you can increase the downward pressure with care.
You will probably still have to shave twice a day but the the hair will have been cut clloser to the skin.
In terms of cosmetics....
I agree with Amanda that an orange/red colour can be good at disguising a dark shadow.

I also agree with Kate that a common solution is Dermablend, but I also it is very hard to wear for long periods. If you have a heavy dark stubble then this is probably the only product that will work as it is a thick theatrical style oil colour. However please note the following hints:
1) It is quite expensive and you may struggle to find the right colour for your skin
2) You need to by the Dermablend Fixing powder to go with the colour to fix it
3) If you have greasy skin it tends to make your skin sweat underneath
4) Invevest in a good make up remover, this stuff can really clog your pores and cause spots if not cleaned off properly
BUT.... If you have perfected the art of shaving closely, or have finer facial hair, there is a really great product in the "Rio" Brand called "Skin Camoflage". This retails at about £30/$60 and is a complete kit complete with instructional DVD.
The kit contains a set of colours to blend at home, brushes, pads and fixing powder. Because the kit has multiple colours (4) you can even contour the shape your face with the product. Dont worry if the tubes look small, the coverage is fantastic from only a small blob on your finger.
The result is half way between dermablend and a normal foundation, but it can be worn all day, and is resistant to water. The only thing you need to ensure is that you have a good make up remover, as it will resist soap and water (and clubbing

). ..and no I don't work for Rio... See link....
http://www.riobeauty.com/index2.htmChrissty