Is it possible for any one to make keyboard letter light up while typing them? With the LED lights?
What I mean: Pressing a letter on a keyboard, then a LED light lights up while pressing the key.

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so you'd need a suiatble transparent keyboard but then you'd need enough space under the keys to accomodate an led. perhaps surface mount leds would be great here. then you'd need to sort out the voltage and resistor for each key. be careful taking keys off because getting them back on again can be tricky.
but I do have a solution: I use a usb-light that hangs over my keyboard - sorry it's not what you wanted - but what you're asking for is a re-design project.
A little bit of searching, and I found one example, and it looks pretty cool. Uh... here are the links:
Luxeed Dynamic Pixel LED Keyboard -Youtube video
http://www.youtube.com/watch?v=uBBfmb6Dsh8
Productmonger page:
http://www.thinkgeek.com/computing/e609/