My progress pic as of 21sep11. Now I'm aiming to do wide pullups and some different variations. Pullups do not only give you wider shoulders but also a good measurement about how slim you are.
People who shy away from pullups are usually over-weighted and with weak back. With stronger shoulder, you will have better posture and better look.
If you cannot do single pullup, please start with this vid.
I know pullups are hard. But if you practice for 6 months along with good nutrition, you can do it.
If you're a man and young, perhaps in 3 months or less.
Pullups are really fun!