I'm tring to decide what to do with a small business. They wan't to know if they should get a server or use one over the internet becuase they want to run a business application and due up-to-date file sharing. They are useing a server over the internet for file sharing presently. But they also have Office live which I think can run programs on it as well. They also want to be able to access the files from everywhere useing a Remote Desktop on one of the Main desktop because they are sick of using a third party connection to pay for it. They have 5 computers wireless and a SBC 2Wire gateway useing DHCP. I don't know how to configure the gateway to get the remote desktop. What is the most cost effective way and how do I configure the network?

IMO you really don't want to run a LAN without some kind of local fileserver. A basic NAS box might be sufficient rather than a full server, though I'd advise getting a box that supports proper file sharing. Personally I'm a big fan of the Linkstation, though the interNAS/NU54 has a better user interface.

I went the peer-to-peer route for a few years and all too often files would go missing because the computer they were on had been moved or reassigned or failed.