Use Campfire with either Safari, Firefox, or Chrome? Then you're going to like this.
Now you can drag a file from your desktop right into your Campfire room and the file will automatically be uploaded to the room. You don't need to click "Upload a file" in the sidebar and go through that process anymore. Just drag a file right into your browser window and up it goes.
Note: This only works with Safari 3+, Firefox 3.5+, and Chrome.