I have a sony car radio. Model # XR-C720 I lost my manual for it and
Im trying to find the wiring layout for it so I can wire it to my car.
So I know which wire goes to which.  Maybe you can find the wiring
diag. on the Web.   Thanks

Hello,

There are palces where you can buy a new manual for you car stereo:
at http://www.treasurechestcorp.com/Sony.orders.html
and www.ElectronicsRepair.net they have the manual you are looking
for. I costs about 5 to 15 $ to have them sent to you. You can also
check www.User-Service-Manuals.com, but I didn't find your manual in
there. But probably the best thing you can do is to surf to the sony
service and support site, they will probably provide you with a
cheaper (if not free) manual or just the page with the wiring diagram.
Most companies don't have their manuals online, but they do provide a
new one for people who lost it.

Links:

sony support:
http://www.sony-europe.com/mcp/moj.x?tid=5
http://www.sony.co.jp/en/SonyInfo/Support/

order manuals:

http://www.treasurechestcorp.com/Sony.orders.html
http://www.ElectronicsRepair.net 
http://www.User-Service-Manuals.com

search terms used:

manuals sony
://www.google.be/search?hl=nl&ie=ISO-8859-1&q=manuals+sony&meta=

hope this helps you,
greetings, cubist