Visiting other worlds

Is it possible, for example, for a character from Guild Wars Prophecies to visit another world from, such as Nightfall?

Thanks!

Yes, for that to be possible, you must own the corresponding chapter (Nightfall if your character is from Prophecies in the original GW campaign). You then use the interconnecting quests:
http://guildwars.wikia.com/wiki/Port

You must also add the new campaign to your existing account. Do NOT start a new account or you will not be able to take your original character to the other campaign without a long session with PlayNC support.

make that a very very long email battle to the point of wasting your time.

Thanks so much for the tips!