I have a 2003 Mitsubishi Eclipse Spyder GTS. Just wanted to add that the instructions posted by kiger work fine except I had to have the key in the accessory position and not the off/lock position ... Then it worked.
Also you need to reprogram all your remotes. I bought 2 new ones, went through the procedure to program the 2 new ones and then the original did not work. So I repeated the procedure again for all three remotes and all were good.
There are other sites that have instructions also which you can google for. The one below also had a good pic of the pin-outs for the connector so you can make sure you jump the right pins. As kiger posted, if you use 2 big paper clips, one in each pin hole (1 and 4) and then touch them together after you turn the key in the ignition it works well and you can do it while sitting at the wheel instead of having to lay on the floor, i.e put the paper clips in the pin holes, sit in front of the wheel, put the key in and turn, touch and hold the clips together and then press the hazzard button 6 times, etc.
http://www.programyourremote.com/cla...yAd.asp?id=966