The logo link that appears in sigs here is quite different to normal html you need for web pages. You can see how to make sigs here: http://www.bykimbo.com/ebid/help/addingsig.htm but that won't help you with your original query.
I haven't looked at Jewel's basic html guide, but it sounds like just what you want. I do have my own basic html guide, but it's specifically for writing auction listings and it's on (cough) another auction web site. I really must do something with that sometime!