Quote :
The Problem: When you're jet-lagged and you have hundreds of photos to edit, sort, organize, and caption, you don't want to do any more work than you must. While it's easy to simply export or email a few photos at a time out of Picasa to upload and title, caption, and tag in Flickr itself, I wanted to caption my photos once in Picasa and send that information to Flickr. I also wanted to organize my photos into sets—or "albums" as they're called in Picasa—and mirror those sets on the web and the desktop.
Get the details here perfect your picasa to flickr workflow