gazz:
Now, i may be stressing my arduino by doing this, i believe the max current that should be drawn from any 1 pin is 20Ma.... and i have just realised i am running about 10 white led's off one pin for the instrument backlights.. oops,
Max on a pin is 40 mA but 20 mA is recommended as most.
Max total you should pull from an UNO is 200 mA.
Feed a transistor to power the backlights. Each should have its own resistor. For higher power there are Darlington's (ULN 2803 has 8 in one chip I believe, can run 500 mA 30V) and FET's (FET's are -very- static sensitive).