What good taking pictures with your iSight camera if you're not going to share them? With FlickrBooth you can upload them to Flickr and YouTube.
This plugin for Photo Booth is fairly easy to install. Once you have it set up you'll see how easy it is to use. Select the photos you wish to export and open up the FlickrBooth window.
Make sure you have a YouTube or Flickr account and that you're logged in. The program will allow you to add extra information like tags, title, privacy level and which set to join the pictures to if you're exporting them to Flickr.
You'll also get to choose from three different actions after you've taken a snapshot with Photo Booth, including automatically upload. I'd advise checking 'Prompt for Information' so you can enter details for the photo and check it's all good before upload.
FlickrBooth is a popular plugin for Photo Booth and that's surely in no small part due to its simplicity. It manages to really blend in with Apple's webcam snapshot program.
Obviously it would be nice to have the option of exporting to other online services than Flickr or YouTube, but considering how popular these are, there's hardly much to complain about.