Thanks for the help guys.
I am sorted out for the 2n2222 and some 270ohm resistors that would only need 2.75mA to saturate from the arduino.
I still need to find a way to run the 1W LED. So i gather a MOSFET is a good way to do this? I have found the MOSFET IRF3205/IRF3710.
Datasheets (respectively):
The 3205 should be fine. Although can anyone tell me from the graphs in the datasheets how much current at 5v is required to saturate for a 350ma collector for the LED?
SirNickity said that a 220 ohm base resistor on a FET would be fine - is this for my 350/500ma LED?? Whats so good about a MOSFET - do they have low saturation values?
On a side note - i thought arduino could supply 40ma through the output pins not 20ma as Henry_Best said? And up to an Amp (although i wouldn't) out of the 5v pin?
Also what resistor should i have between the 5v arduino output and the led to stop it drawing more than 350ma? That is the real question for me!!!
My best idea at the moment is to run the LED using a 2W 10ohm resistor - will this limit it to somewhere between 350-500ma (recommended)?
But i still need a transistor to turn it off and on... 