Jim - An idea that might assist you. As Larry notes, it's necessary to have the letters and any numbers laid down in reverse on the stamp you wish to make to use as a guide. If you're artistic, you just might be able to draw those out, but there's an alternative way that might work for you. Print the stamp out in a font that pleases you, then xerox it on a high-resolution copy machine (or, if you have a laser printer, you don't need a copy). Then rough the flat surface of your stamp a bit with a 1000 grit waterstone, or the equivalent oilstone or sandpaper.
You must then clean the surface of the slightly roughend surface with acetone or laquer thinner to remove all traces of any oil, from either an oilstone or your skin. Then carefully line up your printed template with the printing against your stamp, and run a hot iron over it. The plastic resin that forms the image will be transfered (in reverse) to your stamp, which then gives you a guide for engraving.
One other comment - there are two types of stamps, incuse and relieved. Planemakers of old often used the relieved type of stamp, where the letters were cut into the block, and the resulting stamp in wood had the letters raised. Incuse stamps are the exact opposite - the letters are recessed when struck into wood. In my opinion, the relieved stamps are easier to make and hold up better, but take more force when struck into the wood. The incuse stamps are harder to make, but easier to use, as they're pushing less wood out of the way to make the mark.
Finally, there's another way to make an engraving other than physically removing steel with a graver or a needle file. One coats the steel surface with a relatively thin layer of molten beeswax and allows it to harden. Then, carefully cut away the beeswax where you want the engraving, and drop concentrated nitric acid on the face. The nitric acid will eat away the steel where you've removed the beeswax, but not where the beeswax is still there. I know this method will produce some exceptionally clear images on steel if done with skill, but I don't know if it would be deep enough to make a usable stamp.