First you need to activate the “Your Flickr upload email” functionality in your Account settings in Flickr. It will assign you a special email address that will automatically post your photos onto your Flickr site. So all you do is send an email to this address and it takes care of the rest. The subject line becomes the name of the photo. The body of the email becomes the description of the photo in Flickr. You can also set up a default tag in your Flickr settings that can be assigned to all photos sent via this email address, or you can type tag: xxxxx in the body of your email to add additional tags to your photo.

If your emails are getting bounced back with an error message from Flickr, there is a work around where all you need to do is change your “uploading by email” address to something other than the initial address Flickr assigned you by clikcing “reset” under the “refresh your address” section in your account settings. Not sure if this is specific to the iPhone, but this definitely solves the problem. Enjoy.