I know this is a old thread but for the south Jersey people I ordered a keyless entry remote along with a uncut key for my 2006 Titan off of Discount Keyless on Amazon. I had the key cut at a locksmith but he was unable to program the key. I took the key to JR Flood locksmith in the Berlin Mart in Berlin NJ and the guy programed it for free. The dealer wanted 65.00 to do the same thing. Key and remote work great and it cost me less then half of what Nissan wanted for just programing the key.
I got remotes and chip keys off Ebay really cheap from Remotes For Less, for my daughter's Titan and my Ford, and had them cut and programmed at a local locksmith and Walmart for $20 . On the Ford, if you have 2 keys, you can program the rest yourself in-car. Maybe you can do the Titan also, I learn more about them every day.
RE: 2004 Titan SE. I purchased 2 chiped keys from EBAY, had a local locksmith cut the keys, and am now trying to find someone to program them. I have two good working keys, and saw a thread on here somewhere that gave directions on DIY key programming. Anyone know where that thread is, I would like to give it a try?