there are a few steps that i dont have memorized for exact detail but i can give you enough to do a little google searching for fine configuration.
1. check out the links in my sig for setting up your ssh keys, this will make life simpler.
2. you will need to enable X11Forwarding in your sshd.conf, again check google for exact details for notes on your distro.
3. on the server you will need at least xauth installed, no need for a full GUI.
4. you wll also need what ever tools/applications you wish to run via X11 forwarding installed on the server. ie: if you wish to browse the web, then your favorite web browser needs to be installed, same for mail client, chat, etc... you can even run OOo and perform your productivity applications via X11. Heck ive even run the GUI front end of a VM via X11.... WARNING... doing that is very very very painfully slow.
5. you will either require a static IP at your home, or some type of dynamic DNS service so you can have access to your home LAN 24/7 without worrying about your IP rolling.
6. configure port forwarding (port 22) to map to your servers LAN side IP.
on your client (laptop im guessing) you would just issue a command something like this:
and once connected you can fire up your applications via CLI commands.