If you're fairly proficient with corel, illustrator or even photoshop, here's a step up from the original idea of scanning and saving your signature.
After you've scaneed and loaded your signature into your favorite agraphic program, open a new layer above the original scan and "trace" over your signature with the pen or line tool. Once you have a rough outline of the image, covert it to curves and use your select tool to "massage" the lines into the exact shape of your signature, add the approriate storke or outline weight, optimize, save for web and you're done.
An additional advantage is, that you can change the color of your signature to match your site color's
Eric