using this calculator might help:http://led.linear1.org/led.wiz
it typically produces a design with the lowest possible value for the CLR. For example, for two LEDs in series, with forward voltages of 2V and forward currents of 30mA, you can use a single 180 ohm resistor. The calculator suggests a 1/2W resistor, but realistically you'd be just fine with a "standard" 1/4W size - it only needs to dissipate 162mW.
Something to be aware of is that if there is a significant difference in the forward voltage of the two LEDs used (i.e., a standard 1.7V red diffused LED on top and a superbright 2.2V on the bottom), then you can still wire them in parallel, but each branch should have its own CLR. This will prevent the bigger LED from using up most of the current and dimming the smaller one.
Here's some more useful reading on the subject:http://www.kpsec.freeuk.com/components/led.htm
The calculator above suggests a series array, but you could figure out the numbers pretty easily for a series array if you're handy with basic algebra. Just remember that voltage is the same in parallel, so each branch of the LED circuit will use 9V. I can try to draw you a schematic if it would help.
use the copper brillo pad to rough up the "scrote" to ensure good contact