how to wire the toggle switches I bought

I bought a couple of switches simillar to this one,

I have wired switches before, but they all had 2 pins, this one has three.

I have no idea how to install this, can someone help me ?

This is what we call a single pole double throw (SPDT) switch. It has one moving contact that can bridge two different pairs of stationary contacts. Long story short, this is the most likely scenario: with the toggle on the left the center and left stationary contacts are bridged and with the toggle on the right the center and right stationary contacts are bridged. To make sure that's the case with yours, I would recommend testing it with a multimeter. Sometimes manufacturers do stuff strange.

well the first question before we can really help is what do you want to use the switches FOR? If it's to turn your PC on, then it's the wrong kind of switch - if its for lights or something like that, then it'll work. From the 3 pole design, I'd guess it actually has 3 positions too (although that's definitely not definite).

In a nutshell, the 2 pole switches you've used in the past are either open or closed and that's as complicated as they get - as a result, it doesn't really matter which way they're wired. This one will either have a "circuit 1 on, circuit 2 off" / "circuit 2 on circuit 1" off setup, or possibly if it IS a three way switch, "circuit 1 on, circuit 2 off" / both circuits off / "circuit 1 off, circuit 2" on setup.

If you don't have a multimeter to test the contacts you can go to this page: http://www.ck-components.com/7000/toggle,10598,en.html and download the 7000 catalog pages, as long as you know which one you got it will tell you which pins are for which setting.

so something like this could be used for a dual cathode (2 color) system? AKA
r = red cath, b = blue cath, g = ground, [] = pin, {} = switch position
[] [] []
R G B

switch
.......{}
I = [] [] []
......R G x
...........{}
O = [] [] []
.......x G B

Yes, though the 'I' and 'O' markers aren't strictly correct since in each position one of the things would be on.

If you don't have a multimeter then a flashlight bulb, batteries, and a bit of wiring can be used to test all the combinations of the switch.

Agreed, that one looks like a generic SPDT. Center pole is probably ground, edge poles can connect to separate circuits; one of them can be ignored/unused if you just want to use it as an "on-off" switch.