There is still lots of time to share your monochromatic photos. Check out Carmi's blog at Written, Inc for the rules and to get links to others' terrific photos.
Addendum (7/26/08; 6:00 pm):
The response to this photo has been very gratifying and I've been asked how I did it. So, in the spirit of blogship, here are the steps as I wrote them for Smarmoofus who has a couple of great shots at her site.
When I decided I wanted to do something to save the photo of the truck I knew it was to just isolate the rusty red color. I knew this could be done because I had seen it in wedding portraits, etc. Since I already new I could transplant heads from one group shot to another (that's a whole different story) bleeding out color should be a piece of cake! (So were the head transplants, actually)
I use Photoshop Elements 6 and bought the detailed manual, which contains the secrets to Elements.
1. The first step is to open the file in full edit, then create an other layer with Ctrl J.
2. Then select the brush tool by pressing B.
3. In the pop-up menu for the brushes select a medium soft (I like the 65).
4. Still on the options bar, change the brush Mode to color (it's toward the very bottom of the pop-up menu).
5. Next, press D to select the color black. This will serve to change the area you want to b & w.
6. Now you are ready to color, or rather de-color. Just move the brush over the entire area you want to take out the color, leaving color on the focal point(s).
7. If you accidentally color out of the lines you can go back with the erase tool and restore the color.
Tada! You're done! Now do a save as so you don't lose the original, of course. Photoshop will want to save as a .psd file but I change to .jpg so it can be easily emailed or put on the web.