Google has released it's free image management software Picasa 2, today. This is an update to the version Google was providing after it acquired Picasa last year. Some innovative features from Gmail have been incorporated into Picasa in this new version. They include using labels to tag photos and adding a star rating to photos.
Other new features include, easy mailing of photos (using Gmail or the default mail client) and posting to Blogger blogs, password protection of collections, changing file information from inside Picasa, the ability to place a photo in more than one album, creation of collages and improved photo editing capabilities.
I've always loved the timeline feature of Picasa. Clicking on the 'timeline' button, shows all the photos in your collections in chronological order and makes picking one folder out of many much easier. Other well implemented features like selecting different regions of a photo being viewed in it's actual resolution, make this application a must have for effective photo management.