I'm breaking my new "three posts a week" decision but am super excited to have figured out how to add a signature to my posts! This may not be exciting to you but it was a big victory for me - we're talking a two day battle here :) I'll recap how to do this since the tutorials I found were for the old Blogger interface and led me to a bit of frustration :) I'm amazed at how simple this was!
1. Create your signature. I uploaded mine into Photobucket. Copy the direct link for the image (when you're viewing it in your album, highlight the picture and it's the second option).
2. On the right hand Blogger menu, go to "Settings" and then "Posts and Comments."
3. In the second option, "Post Template," insert this code using your image url where I have caps: