Digikam:gsoc2010
digiKam project web site - Mailinglist - IRC channel: #digikam on Freenode.
Project: Non-Destructive Editing
Brief explanation: Non-destructive means that the original image is not overwritten when editing. Instead, the applied changes are stored and a new version of that image is created. Version history can be accessed.
Project: Face Recognition
Brief explanation: Digikam shall be able to detect faces in photos, identify the person depicted and automatically tag the region on the photo with the person's name.
Project: Reverse Geocoding and Improved Map Search
Brief explanation: Using the Google Maps or geonames.org reverse geocoding services, location names can be added as tags to images which already have GPS-coordinates.