I've posted here once about a free software tool for annotating family photos. It is called FotoTagger and it is already used by genealogy researchers and family historians to make family photos more informative. One of useful applications I saw was a blog with annotated photos of inscriptions on gravestones.
FotoTagger lets us place location-specific annotation labels on digital images. These labels can include identification notes, comments about role of a specific person in the family history, links to Web resources that contain additional information, or whatsoever.
Annotation labels can be hidden in a click so there is no risk to spoil an original picture.
Then you can find a particular person among piles of digital photos by his/her name or any other identification comment that you typed in an annotation label.
A few days ago the new version of FotoTagger has been released. It supports Flickr. It means that you can upload an image annotated with FotoTagger to a Flickr account while all annotations will be converted to editable Flickr notes. Similarly, you can download an image from Flickr back to FotoTagger. All Flickr notes are preserved and transformed to editable FotoTagger annotation.
Additionally, annotated pictures can be shared through blogs - direct publishing to Blogger.com and LiveJournal is supported.
I just downloaded this -- it is awesome -- I am working with some 70 year old old photos -- and they are from overseas from hubby's family! We are lucky enough to know a few of the names so we are trying to preserve that knowledge!