I want to put some in my case. What all will i need to make them work?

get 5v led's, and attach them to the 5v on a molex. that's the simplest. or buy some ready made ones. if you want to use lower voltage leds you'll need to fiddle around with resistors and stuff

you can get 5V and 12V leds that have an integrated resistor... so basically you can hook it directly to either a 5 or 12 volt line in your computer...

otherwise, with regular leds, you have to calculate a resistor and hook it up in series to limit the current, otherwise you run the risk of burning out the led, burning out your psu, or both...

you may have to look into the resistor option if you want anything apart from a red, orange/yellow, or green led...

of course, if you are simply replacing the led's in your front panel, you don't have to bother with resistors...

alright thank you both for your help.

Regular leds that any online mod store has with 470 ohm res plugged into 12V molex wire and i beleive 75 ohm for 5V
need a place? they ship world wide and fast
http://www.adpmods.com/case-modding/home.php?cat=105