How do I set a Canon PowerShot S3 IS so the date appears on the photo when I download it and/or print it?

The date and time (and a lot more) are stored with every picture in its EXIF metadata. Any photo viewing/editing program should be able to display this data. To print this data, please consult the documentation for whatever program you're using to print your pictures. Depending on the program and printer you may print the date on the image, in the margins, or on the back.

Most modern Digital Cameras dont actually stamp the image anymore. the data is recorded in "metadata" in the image file. But if you use the ZoomBrowser software that came with your camera to download images you can do the following:

1. Adding a Time Stamp to a Printed Photo:

After selecting Print, check the box(es) "Shooting Date" and/or "Shooting Time."

2. Adding a Time Stamp to the .JPEG Image

Select "Insert Text...," click in the image where you want the stamp placed then click "Import Shooting Date/Time."