Tournaments and Ladders?

I havn't actually played GW yet but am looking forward to it from everything I have read. A question I do have though is what exactly is the deal with the Tournaments and Ladders I keep seeing mentioned.
Are there actual set tournaments at a specific time and place like a sports tournament. Or is it more of a general ranking based on your PvP combat experiences in game.
If anyone could explain to me how these work I'd appreciate it.

At the moment there is only an official ladder. In Korea they have a tournament going, but gaming is big business there.

There's also an unoffical guildwars league started, you can read more about it on www.gwgleague.com or by joining /server irc.gamesurge.net -j #gwgleague.

So now i have heard it all gaming is not big in the US, Darn it I thought I got my kick arse pc fr gaming silly me.

So where do the stats for the ladder come from? Are they general stats from your performance in missions during normal play. Or is it how you do in structured tournaments?

i'm sure there'll be tons of unofficial leagues setup.

http://ladder.guildwars.com/

This is the only existing ladder at the moment, and the stats are based on GvG matches.

Hehe, everyone seems to keep missing what I'm asking so I'll rephrase. Can you advance your guild rank through normal GvG play or does the ladder only use set tournaments.
On another note what is the purpose of the tournaments? Is there a prize or is it only for fun and to work on your ranking etc.

yes through GvG and general PvP, and no i dont believe there are prizes as of yet, but therte could be some included in the future, for now its generally to say i kicked your arse better than you kicked mine

At the moment, all GvG matches affects your guild's ladder ranking, and there are no other way to improve your ladder ranking.

And no, there are no prizes.

I don't want to turn this into a plug thread, but the IGA (International Guild Association) is another third-party Guild Wars league that started a few months ago. The site is still in developement, but it just goes to show that there will be other tournaments and such besides the official ones.