Xmp Manager is a GUI to manage XMP metadatas on GNU/Linux.
Currently XmpManager is a very experimental software and it could not work as expected. The features implemented are minimal.
Why should I use metadatas?
Metadatas permit to attach more info to your files, ex. description, author, coordinates.. This datas are embedded in the image file, so you won't lose them even if you'll upload the image on a website or you will burn this image on a DVD.
Here a screencast.
Why should I use XMP?
It support 'title', 'description', 'creator' fields (but It is very easy to add new fields)
It writes metadatas on-the-fly
It support multiple image editing
sudo apt-get install libimage-exiftool-perl ruby-gnome2 nautilus-actions
An set Nautilus-actions similar to this:
There are many things that is possible to do, the priority is a complete xmp fields support and then the selection of the tags(keywords) in the folder with checkboxes.
Embedded geotagging via Google Maps is for 1.0
Windows Vista is among us, even if I don't plan to migrate to Vista, but Windows Vista Photo Gallery is very well done and probably is the only killer app I see (The unique thing that Beryl can't do :D).
F-Spot and other OSS tools still don't implement XMP in a user friendly way.
Xmp and Flickr
Flick supports import EXIF, but it doesn't export anything so your geotagged photos with coords and description will be locked in Flickr forever, think about it!