My friend just recently bought a ps3 and he wants to connect it online and i don't know if its possible because the only internet he has comes from a T-mobile network dongle he plugs into his laptop. just wondered if this was possible to do? 

That should work as long as the laptop has a wireless network card integrated which most newer laptops have.there is youtube tutorials on this, he needs to make a seperate network on the laptop or something. mate has done it with his 360, same principles for the ps3 from what ive heard.
Disadvantage is that the laptop has to be on to be able to have a network connection on the PS3 but it should work.
...the only internet he has comes from a T-mobile network dongle he plugs into his laptop.
Ad-hoc wireless network + internet connection sharing = win
Su