I just got this from the Help section of Photoshop Elements 2.0

Adding file information

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In Windows, you can add file information to files saved in Photoshop, TIFF, JPEG, EPS, and PDF formats. In Mac OS, you can add file information to files in any format. You can add information such as the image title and a caption, and copyright information.

Note: File information cannot be saved in GIF format when converting a file from a different format.

To enter information about a file:

Choose File > File Info.
Enter the desired information in the File Info dialog box:
Caption to enter text that can be printed under an image or displayed in a Web browser's title bar. To print the caption, choose File > Print Preview, and select Caption. Then print as usual. (See Setting print options for more information.)
Choose Copyrighted Work from Copyright Status to display a copyright symbol in the image window's title bar. Enter the desired text in the Copyright Notice text box. Specify a URL in the Owner URL text box if information about an image can be found on a web site. Click Go To URL to test the link.
Note: If Photoshop Elements detects a Digimarc watermark in the image, the Copyright & URL section is automatically updated.

EXIF to view information imported from your digital camera, such as the date and time the picture was taken, resolution in ppi, the ISO speed rating, f/stop, compression, and exposure time. For more information about EXIF annotations, see your digital camera documentation.
When you've finished entering file information, click OK.

I haven't tried it yet, but hopefully this is what we're looking for. And if Photoshop has it, there's a good chance the other popular software packages have something similar.