Picasa is really nice for editing photos, Flickr is great for sharing them. But, they are owned by different companies (Google and Yahoo) and each company seeks lock-in. Picasa is therefore hardwired to Google’s Blogger service.
Jim Rutherford on http://www.digitalmediaminute.com/article/1299/gmail-picasa-and-flickr has put together a nice procedure for automating the upload of the groovy picasa application to the groovy flickr website.
I plan to support direct integration of flickr photos onto this site, so if you want to get started, that’s the direction I’d advise.