Time management

I can't spend my time rationally and i hate myself for it!
I have to do my homework, read a book (exams are very soon), but I'm surfing the internet, reading twitter, watching "Friends" and doing nothing.
How do I force myself to do real work?
I'm burning with desire to study, to be successful in work, but i'm so lazy.
The lazyness is eating me inside.
Every evening i promise to be clever, positive, active, but in the end i lay in my bed watching the episode about Rachel's kiss for example.