If you select 'All' in Lightroom's metadata panel it should show you the S/N of the camera directly under the Make. Or at least it does for all the Canon cameras that I have used. It's also available to view in IEXIF Viewer although it's highly improbable that you'll be able to locate an image taken with your camera from those posted on the web.
With the 7D (and probably other later Canon cameras) you now can add copyright/owner details directly from the camera itself which then appears in the EXIF data of all images taken with the camera.
« Last Edit: May 30, 2010, 05:12:25 PM by Forseti »
Canon 7D, Canon SX1 IS, EF100 f/2.8 USM Macro, EF70-200 f/4 L IS USM, EF17-40 f/4 L USM, Sigma 50mm f/1.4 EX DG HSM, Canon Speedlite 580EX MkII
"Everyone can take a great picture with digital, the knack is to take two" - David Bailey