Today I found a terrific app created by kouiskas here on deviantART that allows images in iPhoto to be uploaded to deviantART Sta.sh. From there it can be submitted so a deviantART gallery.  The app, in fact, offers to take you to your Sta.sh once the upload has finished. I was able to upload directly from my Photostream, in fact, without having to first import the image into my library.
From the page below select "Download," which will put a zip file on your HDD. Extract the installer application from the zipfile and run it. It installs the app into your Applications folder. I ran the app from there and didn't notice anything happening, but in fact something did happen: the app began running in the background and its icon appeared on the menubar. From this icon you can check for updates and browse your Sta.sh.
To upload to your Sta.sh, open iPhoto, select the file you want to submit, then select File/Export from the menu. You will see a window that looks pretty much like the thumbnail here.  Click the button and after the upload go to your Sta.sh to finalize the details and move it into your gallery.