Button Buddies

I need a few good people to help me put the all-important button on my blog. I hear all the cool blogs are doing it. I already have a cropped and sized picture ready to go . . . I just don't know how to get it on my blog. My blog is perfectly content to sit in the corner and watch the other guests at the Blogosphere party mingle, but I think it's high time my blog got a button of its own so it can get out there and mingle, too.