A reader sent me this handy link that the folks from CMP.ly offer for bloggers to be able to comply with FTC guidelines on endorsement from bloggers. There are several different CMP.ly "labels" available to mark exactly what your material connection to the product discussed it, ranging from the above "No Connection, Unpaid, My Own Opinions", to http://cmp.ly/5 to disclose an "Affiliate marketing link".
Unfortunately the labels don't come as pictures (yet), so you can't easily make a graphic label link. But it can't hurt to put a text link like this to the appropriate disclosure label into a review on a blog.
[EDIT: Some comply labels as funny pictures can be found here.]