another way to get an alpha is to pick your favorite font, and enlarge it
I usually make the font really large, copy that, rasterize the layer, and then add a stroke in a contrasting color to it.
i use the original text layer, move it on top of the new stroked/rasterized layer, and then add a slight shadow
it is a quick and easy way to do some title work or add an alpha-like text to your pages
have fun with your siggie :)