So....

I have bought factions, and not going to play the game for aw hile, i just added the cd key to my account, is it possible to play my character from prophesies and transfer him to the world of cantha? or something.

Yes, you can. There's a quest you get in Lion's Arch that will lead you to cantha.

It works both ways. There are quests in the main cities of both worlds to transfer characters made in different games to be able to play in the others.

I see a lot of people asking about "transferring" characters. I guess this must come from WoW or some other games where you have to go through quite a process to transfer characters from one "server" to another.

You do not "transfer" characters in Guild Wars. You simply gain access to more territory. You are as free to go back and forth from Lion's Arch to Kaineng Center (and back) as you are to go from Lion's Arch to Ascalon City, and it's just as easy (except you use the boat - and once you've done the appropriate quest.)

Prophecies characters wishing to travel to Cantha for the first time from Tyria should seek out Firstwatch Sergio in Lion's Arch and take the Mhenlo's Request quest.