Most outdoor outfitters carry camp showers, but the trick is setting up a showering area that will provide clean feet and privacy.
Clean feet can be had by building a platform similar to the table shown above, except that it need not be lashed to any trees - it can simply lie on the ground. If you do not build a platform, you will create a mud hole when you shower, and then everything will be clean except your feet. Somehow the mud on the feet have a way of migrating elsewhere too, rendering the whole showering experience an exercise in futility. Don't scrimp on the rope when attaching the spars to the poles - the platform must be secure and stable, and the spars must not roll around. Lash them down securely.
For privacy, you can bring a tarp, and string up an enclosure using trees for support. Make the enclosure large enough to hold a chair so the freshly cleaned Pathfinder can remain freshly clean as he/she dries off, gets dressed, and puts on his/her shoes.
Another option is to buy a shower tent which is a small tent tall enough to stand in and equipped with mesh around the edges of the floor. This allows the water to drain out, but allows the camper to stand on an otherwise regular tent floor, thus keeping the feet clean.
