Light facial detail in my Nikon D60

Could have different causes. If you are using an Nikon flash, you should put it on TTL and your camera on automatic to check everything is working correct. Then you can change to all other modes and the camera should also tell the flash when to stop.
If you are using an other brand, or a wireless trigger, you have to adjust the camera settings yourself. Not knowing what flash you are using, and not knowing what settings you have dialed in on your D60, this is the first thing I can think of.
Perhaps if you keep having trouble, you give me some more details and I hope to be of any help then. Just a quick question. How is the light on the pictures when you shoot normal? (Without flash)

The easy solutions are: Check your lens to make sure it's fully mounted and clean on both the inner and outer glass. Check your sensor for smudges (cleaning this is a challenge). Make sure you have enough lighting and contrast on your subject as low-light may reduce the ability to focus for some cameras. Good luck!

elis - did you ever solve this problem? the same thing is happening with my d60 and i don't know what to do!

Yes. The expore time is long when you picture at night. Use the flash or TRIPOD! ;) The other way is to change ISO. It's better if you change is to 800, or 1600 or 3200 but be careful, there will be a lot of noise then! ;)

I have had "dark pictures" from each of my Nikon DSLR (D70, D80, D200, D300) cameras usually when taking pictures from a tripod and/or the self timer. Situations where you take your eye away from the viewfinder which allows stray light to enter thru the viewfinder and throw the auto exposure way off. Not sure if this is what is happening to you.

The Nikon D60 does not have "live view" capability, so you'll need to use the viewfinder to frame you shots. If you need "live view" capability, consider purchasing the D80 or D90 instead with offer the feature...

Have you tried turning off your active D-lighting? Also try turning the knob to Program mode "P" on the dial, take a few shots, then go back to auto and try it again. If you have further details, it would be useful...

Read up on exposure and take the camera out of Auto mode.

Quick solution: enable the "auto ISO" setting in the menus. This will automatically recognize low-light conditions, and adjust the ISO accordingly.