[zoltz]

Not sophisticated, and only a first step to get some kind of traction, but using it can make a real difference to me:

a) Define your main project

b) Choose an activity that you like and that comes naturally as procrastination

c) Choose a reasonable time ratio between them, and respect it

As an example, every hour of surfing the web has to be (sooner or later) compensated by three hours of work on the main project.

[euccastro]

It feels better if you do the same backwards: for every x hours of work on the main project you reward yourself with an hour of surfing.

Also, saying you have to do something is disempowering language that drives you to rebellion. Remember yourself why you want to do it. Think of the consequences of both doing it and not doing it. If after that you still don't want to do it, don't do it.