Although various utilities and plug-ins exist for creating frames, mattes, and borders, I find it handy to do this directly in Photoshop while working with an image. My objective was to produce mattes and frames similar to what I would do in the analog world for gallery presentation. Here's the procedure I use:

1. After retouching, editing, etc. the hi-res scan of the image, reduce it to a size appropriate for Web presentation.
2. Select the entire (reduced) image, and copy it into the memory buffer (CTRL-C).
3. Open a new image window, the size will default to the same pixel size as the copied image.
4. Add four pixels to each dimension, then click OK, and the new image window opens.
5. Select the inner matte color (black, perhaps?), then fill the (still blank) image window using the paint bucket tool.
6. paste the copied image - it will be centered in the black background by default,
7. Flatten the layers, then select and copy the combined image (CTRL-C again).
8. Open another new image window, as above, but add 100 pixels (or thereabouts) to each dimension.
9. Select the outer matte color, and again paint-bucket the background. Texture can be added, if desired, using one of the Image->Render tools.
10. Paste the previous image (the pic plus the inner matte).
11. Flatten the layers again, select all, and copy.
12. Open another new image window, as above, but add 8 pixels to each side.
13. Fill the background with black, or whatever color is desired for the "frame".
14 Paste the pic (outer and inner mattes, and the real image).
15. Flatten the layers again.
16. Select all, and copy.
17. Open the final image window, adding 30 pixels to each dimension. Leave the background white.
18. Paste the "framed" image, and then move it close to the upper left corner.
19. Use the Layer->Effects->Drop Shadow tool to add the shadow. I like to use a value of 15 pixels for the shadow and blur, and I adjust the angle to 130 degrees.
20. Flatten the layers again, and save as a JPEG, adjusting the compression for the optimum balance between image quality and file size. Add the copyright notice with the Text tool after the JPEG save. That way, the text stays crisp. Flatten the layers and save again.

Simple, eh?