Flickr PM - Forked by me :
I use a lot this Greasemonkey UserScript : " It Adds easily accessible icon links to a users FlickrPM popup mail, next to their user names in Forums/Pool/Favs/Sets and photo comments. It also allows you to send a flickr mail to a user without actually leaving the page you are on."
I tweaked it to add new links/icons for Others Applications (see the screenshot). Some working links: