Personal Bridge Scorer is a Palm application that allows you to keep track of your duplicate game results without having to go find a pencil! It's also great for allowing you to leave your convention card on the table, never having to pick it up and turn it over several times a hand.
Personal Bridge Scorer is free to use. If you find it useful, there will soon be a donate link where you can send me money (to pay for bridge entries of course!) Either way send me suggestions -- there are lots of ways to improve this tool.
If you don't have a Palm device, you may be able to buy a cheap Palm/Handspring off of EBay. I suggest getting a model with color (it just looks better :) and potentially a rechargeable battery.
News: New version coming soon that fixes a bug with the Find Game feature. iPhone/iPod Touch version is under works!