Any site I find myself spending too much time on gets blocked in my hosts file. I still have them available on my iPod Touch. When it's time to work I put the Touch across the room.
Since the temptation to read news usually only lasts a second or two, this keeps me on task.
I do the same. I have a script that will update my hosts file at the start and end of each day. All my bookmarked sites are blocked during the work day.
This reminds me of me playing games.
When I was playing a game too much, I deleted it right away with all the save games so the hussle of reinstalling was too big and I lost interest.
Since the temptation to read news usually only lasts a second or two, this keeps me on task.