Search; It has been discussed and I've provided links to what you need to get. You can buy it from eBay for about $20. The only thing you need to watch is the two terminal locations.
I'm running resistors, but only because I have to (you may as well). I upgraded to the timed relay, but the switch on the bars is of such a shotty quality that with just the LED signals, the opposite side (for instance, if you turn on the left signal, the rights light up too) will light up. I installed one resistor (5 ohm, 25 watt) per side, and it works perfectly.
When I swapped my rear signals for LED I had to add resistors. Check what the resistance is on the new lights and subtract it from the stock light total then add in the required amount of resistance,( i bought mine at the source by circuit city)