google this:
creating an html email signature
or
adding a logo to an email signature
It should give plenty of links to explain how to add a logo to your email signature. (I'm assuming you want it in your signature at the bottom of your emails)
I can't remember exactly, but when I wanted one for my wife's email, this is how I found out how to do it. I'd tell you otherwise, but I've slept since then. There is a way to generate html code with a link to the logo that you can copy and paste into the signature preferences of your email. The way I did it to get everything positioned right was to create the entire thing as a graphic (type, contact info, logo all as one graphic, that way, I didn't have to worry about the position and size of the logo in relation to the text. The only drawback is I had to sacrifice the live links to the website, so I added the website link again as text after the signature)
