Create a Space on http://spaces.msn.com if you don't have one

Go to 'Edit Your Space->Settings->Email Publishing'

Turn on Email Publishing (screenshot below)

Choose a secret word (screenshot below)

Create an account on Yahoo or Flickr if you don't have one

Go to the "Add a Weblog" page at http://flickr.com/blogs_add_metaweblogapi.gne

Specify the API end point as https://storage.msn.com/StorageService/MetaWeblog.rpc. The user name is the name of your space (e.g. I use 'carnage4life' because the URL of my space is http://spaces.msn.com/members/carnage4life). The password is the secret word you selected when you turned on Email Publishing on your space.

Click "Next", then Click "All Done"

Go ahead and create blog posts on your space directly from Flickr. You can see the test post I made to my space from Flickr here.