setup a remote desktop interface on it.
You could use the built in windows one (Remote Desktop Protocol if you have windows).
To enable remote desktop on the server computer, right click my computer and go to properties. Here go to remote. Check the box that says allow remote access.
*NOTE If you are using XP home (or I think vista home/home premium) as your file server, you will not be able to use this option, only XP Pro and Vista Business and up have this feature.
Once you enable it, simply go the computer you will be using to remote access the server from and find the rdp application (comes with windows). Typically this is under the start menu under accessories and communications or system tools. When the window comes up, type in the IP address of your server (or name), enter the username and password (as set on the server) and poof!
Else, these are worth checking out.
<-- my favorite
I'm sure others have other great advice about this. This is pretty big when you work with servers that are usually located in remote locations, or at least across the hall in the server room (which requires you to get up out of your comfy chair