I want to add my company logo and and some juice to my contact information in the signature part in Mail.app. How can I do that with little or no efforts?
It's not a huge effort to go through, but it does involve a little effort on your part. I haven't tried this myself (though will try it shortly just out of interest), but the basic principle seems to be to make a .webarchive file and drag it into the signatures preference box.
EDIT: so I went and tried this and it DOES work in the current version of Mail.app, on Snow Leopard. The trick is essentially;
a) create a .webarchive of your desired signature.
Bear in mind that any graphics you put in there need to be graphics that are out on the 'open web', rather than references to files on your own computer etc. I think it's this bit that catches a lot of people out.
b) Go into Mail and go through the motions of creating a new signature.
In the Library/Mail/Signatures folder you'll see Mail creating a new file with a guid-like filename (eg 61F51203-5C18-4061-A8EF-F53B17C41476.webarchive). Make a note of this filename!
c) Close down mail, and replace the contents of that signature file with your webarchive file.The best way of doing that is;
d) When you restart Mail, the new signature you've made will be available.
But I've just been through this and even though I have no use whatsoever for a HTML signature, it does work. :-)