[Staffslug] Setting up linux server behind NAT

HI all i'm new here i'v been playing with the idea of setting up my own server for a while now. I have got ubuntu server 7 running on a system and was wondering how easy it is to set up a server behind a NAT router with a reg'd domain name (from places like 123reg.com etc) for now i'm trying to get it running as an internal server on a LAN with samba running so it can be used as a file server for everyones laptops and desktops around the house but i plan on running a mail server and apache for webserver access and webpages available to the outside world My question is how would i go about getting this LAN server available to the outside world using a domain www.silverrook.co.uk My router is a US Robotics Sureconnect 9106 I'm using the newest distro of ubuntu server 7.10 Adam