robzilla - 10:20 pm on Feb 22, 2011 (gmt 0)
So far so good, indeed, and welcome to WebmasterWorld.
I'm not sure I understand either. Are you looking to replace anchor text with an image through CSS, so that the end-user sees the badge (the image), whereas search engine spiders (or users who have disabled the stylesheet) see a text link? If so, then your question probably belongs in the CSS forum [webmasterworld.com].
I assume you're interested in doing this because anchor text is supposedly more effective than image alt text? You might ask yourself if those who will be displaying your badge on their site are willing to insert the extra in-line CSS into their HTML code, instead of a simple <a><img></a>. Also: you would have to be very careful to write the code in such a way that these sites run no risk of being penalized by search engines (due to hidden text, for example).
I'll send you a sticky with a link to an article about a seemingly successful implementation of this method.