How to upload Photostream pictures to Flickr

http://www.malarkeysoftware.com/projects_PhotoGrabbr.html

This great piece of software will do it.

Beware though, if don't have a pro account, you can't download the high resolution originals.

I use the Posterous Spaces app to save full resolution photos from the roll to the web and have that linked to push to flickr. You could also use the native flickr app to pick them from the roll.