I'm a little confused. You registered yourself with Tripod for web space yeah? Or do you have access to the web from Tripod?
If you have web space with Tripod then you don't need Apache as you will be using their web server. If you have web access from Tripod through something like a cable modem that is attached to your linux box then you need to setup Apache (in httpd.conf) and make sure that you have a domain pointing to the IP address of your linux box. If this is a static IP address then its pretty straight forward, and you can use someone like
http://www.dyndns.org to register a name if you want, or anyone else for that matter. If its an IP address that changes (the lease for my cable modem expires ever hour for example, so the IP may change) then you can use someone like DynDNS again and a script that updates their DNS so the name follows your IP address as it changes.
Clearly this isn't step-by-step but I need to know the first bit - you got web space or access to the web through tripod?
cheers
Jamie...