UeberMensch said:
1) What is the difference between Local Area, ValkerieNet, and Internet?
Local area = LAN. You can play the game with computers in the same LAN. The advantage of LAN-gaming is the stabile and fast connection, plus the (in my experience anyway) more social gaming experience. The disadvntage is of course that people actually have to be in the same place.
MPing through the Valkyrienet is the standard. It is a sort of chat-program through which games can be arranged with people from all around the world (altough basically all CK games are pre-arranged either on the forum, IRC, school etc). There are "rooms" (for CK the obvious room is of course Crusaders -room) where people meet and set up games. Sometimes however V-Net is down, and sometimes rarely (actually never for CK) there are people who don't understand what a private game is...
MPing through the Internet-button requires you have to type the hosts IP address to the field (and if you are the host, obviously it means you have to give your IP to the other players (aka clients) through some means (ICQ, PM's etc). The Internet-method is basically used only when V-Net is down or when you have a private game that is set up in for example IRC.
2) I have an Intel Celeron 2.4 Ghz processor, 560 MB RAM, and a 56k modem. Is that suffcient or must I have DSL?
Your computer certainly is good enough (unless it has a zillion background processes runnin

), and I know EU2 can be played with a 56k modem if the speed is not too high. I haven't (AFAIK...) tested playing CK when one of the players is on modem. I have my doubts of its stability, but I sure would like to find out
For other issues relating MPing, please check the link in my sig.