wiring multiple leds - pc modding

hi
i wish to wire 6 (or x number) of the same led, using a psu - 12v line.
Most probaly it will be an orange led, thought i should say that as
i've read that the actual colour will effect the resistors ..is that so
?
So simply whats the best way .... ?

 

find out the Vforward and Iforward for the LEDs you are going to use


(12 - x * Vf)
R = -------------
If

--
John

thanks.....one thing though
could you elaberate on Vforward and Iforward ((If Vf)?!