what tools do I need to be able to log on to my ubuntu 9.10 desktop from most locations .. school library wifi hotspot etc. By tools I mean software to install/run on ubuntu and what do I do( setup ) to my router( dlink-WBR-310)and a comcast modem to make this work .................by the way I am also running ubuntu9.10 on my laptop..
need help

You can use remote desktop which is available under applications> internet> remote desktop viewer on your laptop. There is some set up involved on your home machine which is done by System > Preferences > remote desktop. I have not set this up on my machine yet so I do not have all of the specifics but you will need to set a port open on your router for the connection to work. By default Remote Desktop uses port 5900 for communication .... for security you can change this in Advanced preferences and make sure that you set the same port number in the router. On the advanced page it also shows the "address" to use to make the connection and if you use a password to connect (in this case sucurity is your friend... use it).
If you do not need full access to your desktop, you could do what I did. Install Apache as a server and you can make a web page that has the needed files on it, however you will not be able to save information back to your home machine using this method, but for security it is a lot safer (HTTP access only on port 80). This method is rather involved and I will not go into all of the details of it as the first method, I believe, is what you are looking for.
If you do not see Remote Desktop viewer under internet or under system > preferences you may have to use a package manager such as Synaptic to load it and then you should see it after that.

Alan