I am not using any resistors, I have been using the drivers made for the LED's. Many of them are rated for the number of 3 watt or 1 watt LED's they can run. If you get a driver that flashes is needs more LED's. For the heat sinks I use the Lowes aluminum "C" ("U") channel found in the hardware section in the metal/aluminum section display bin. I use the 3/4" wide stuff and it works great without a fan, I have used the 5/8" as well but, the 3/4" keeps cooler. For mounting the LED's I use the two sided thermal adhesive stickers from rapidled.com. With these parts I am going to add some LED lighting to my 40G SW as I did my 10G SW and get ready to change all my scrubbers to LED when the new technology scrubber is revealed.
EDIT: I am also using plastic eves-trough as a housing for my LED's fixtures that is lined with the plastic mirror sheets for the reflector.