Many folk often need to access a home computer from Work or some remote location, myself included. If you're connecting a Windows Machine to a Windows Machine it is fairly easy. The protocol that talks between two Windows boxes is known as RDP and works well out of the box. The story is a bit different when you move to Ubuntu (or Linux in general actually). You need to use a protocol called VNC and it is not at all secure on its own.
In Ubuntu you also don't want to rely on the built in Remote Desktop feature from the Administration Menu, that is somewhat lacking in security allowing one to get p'owned... more on this later...
This post will look at connecting to your Ubuntu home computer from a remote location in a fairly secure way.