It is Quiet an extensive project, So make sure you have time!!! These are the same ones I got on my 4.5 gen camry.

It was quiet tough getting them on. It was two of us, I must say I am a bit of a noob too. You must cut parts of your bumper because they do not fit. Just be positive where you want them to be, because once its cut you cant go back!
Installing the bulbs: It is possible to get the HID in there, but you must cut a hole where the original H3 wires run through to get the H3 out. Then you will put the HID the same way, except you will have a a hole where the wires run through. You must cover up that hole with silicone. (I let mine dry overnight).
Now for installing the switch: The fog lights should come with a wires and a switch. I placed my switch in a blank space to the right of the traction control button. Use a flat head screw driver to pop out the piece. The switch comes inside a frame, i guess you can say. You can take out the switch and make it fit the little plastic piece. Cut the a hole where you want the switch to be, fit it in and glue/silicone it. (whatever you do,
DO NOT use Gorilla Glue, it foams and makes a mess)
Running the wires: this took me the most since I did not know how to do it. You must run the wires that were given to you from where the switch is to where you want to locate the balast. You bring in the wires through the fire wall, I believe we had to remove some trim panels towards the foot rest to pass the wire through.
After that just connect the three wires to the switch, pop it into place, then connect the balast to the bulb, and the wires to the balast. (This is pretty self explanatory)
I bought xentech HIDs on ebay for $30. More than likely they will flicker. (I got lucky and mine don't) I suggest spending extra and buying a better brand. Just specify that it is and H3 and you will have no problem with the bulb size.
I have pics on this thread
Update: Fog Lights and Rims (Pics Included)
As for the retrofit, I want to do that to my camry, but I have been checking the forum to see what is the best thing to do(unfotunately retrofitting is super expensive, so that project is on hold for now)
I hope this helped, and Good Luck!!!
P.S(I will try and post pictures of the switch and balast locations)