Beth asked how I created the image below, so I thought I would give you a quick, mini tutorial. I'm using Photoshop CS3 on a Mac.
This look is the result of using the High Pass Filter, and then moving that layer to a new background. I use the High Pass Filter to sharpen images, and while experimenting one day, figured out this quick technique.
1)
Open an image and duplicate the background layer.
2) Run the High Pass Filter on the duplicated layer.

The High Pass Filter will change the duplicated layer into a gray image with the outline of the layer below it.
Depending on the radius setting that you choose when running the filter, the outline will vary from faint, to an embossed look showing more color and detail. The two images below illustrate different results. I used the setting in the 2nd sample.
3) Now open a background document that you want to apply the image to. I used a scan of the backside of an old photo that had been glued to matboard.
4) Drag the flower layer onto the new background document. Your layers palette will now have two layers; a
background and the gray, High Pass Filter layer on top of it.

5) Next, in the Layers Palette drop down menu, change the Blending Mode to Soft Light:
Final result:
Optional: make a duplicate of the High Pass layer for more definition:
You can also use different adjustments to add more color if desired, such as Hue/Saturation, Selective Color, etc.
Have fun!