I got the Getting Started with Arduino kit and i have a question. What do all 4 leads mean on the clear LED? Thank you in advance! 
Sounds like it is an RGB led, meaning you can get more colors out of it and do some cool color mixing. If I remember correctly, the long lead is ground.
If I remember correctly, the long lead is ground.
That is not the most common type. The most common type is common anode, that means the long lead is the + and the other leads go through a resistor each, - to ground or an arduino output pin.
If it is a super-bright LED, or an LED that almost looks like one of the four pin buttons, then you will notice that on either side, both of the leads are connected together, so there is really only one way to hook it up. You with have to find out which way it goes though, if the positive and negative sides are not indicated. Search Google about how to test LEDs.