Does the G10 offer a date and time stamp option?

Not natively. This camera cannot record the shooting date directly on the images it takes.
You can insert those dates when printing images in ZoomBrowser EX, which comes with the camera.

James is correct. There's no way to "embed" the date/time stamp info into the image while you're shooting. However, that info is recorded with the image and Canon's software is capable of printing it on the image when you're making prints. This isn't something I'm very interested in, so I can't give the step-by-step, but I did come across it in the manual for the Image Browser software. You can include other text in the image area if you want, but date/time is just a simple button. Further, if you want to have an image file with the date/time on it, you can "print" a PDF file instead of sending it to your printer. At least on the Mac, that's a very straightforward option.