Crash, What voltage are you planning on running the LEDs off? BASIC rule #1- NO MORE CURRENT THAN 15/20 mA. At these currents the LEDs will be extemely bright. If you are using a 12 volt battery, try a 50k or 100k 1/4 watt resistor. These values will at least tame the beast a bit. (PTN. Try a 100k pot. ie; variable resistor, BUT make sure that you have at least a 1.2k resistor in series with it). This way you can select the final value of the fixed resistor to suit the brightness required. You may be able to do this *instore*, if you ask nicely. One thing tho. DO NOT buy high brightness LEDs. Standard red LEDs will do.
HTH.
L.
ps. Resistor values for various voltages > 12v = 1.2k. 6v = 620 ohm. 3v = 100 ohm. All 1/4 watt. As stated, the LEDs will be very bright with these values.