do you not have an Imageshack/Photobucket account? I really don't recommend uploading a signature to this site, it forcefully reduces the size to fit within its own upload restrictions. I recommend you get an Imageshack account, personally, as a certain level of activity is not required to keep it active.
ImageShack® - Online Media Hosting
EDIT: You can reference this thread for more info: /forum/artwork-graph...otlinking.html
I pulled that thread from the resources thread, stickied in this section. Here's the resource thread URL for good measure: /forum/artwork-graph...opyrights.html