when it says world is full, it will also give you a number of players that are waiting to login. If you stay in the character screen, and keep tring to login, you will see that number is going down, usually it goes down 100 in a minute, so if you have 500 ahead of you, you'd have to wait about 5 minutes to login. If you back out of your character screen, you will go back down to the bottom of the pile.