Linux and "offline folders"

[O. Sinclair]

Maybe someone can assist on this. I have (and am still) searched the 
internet for information on how one can implement the windows concept of 
"offline folders" in a linux client environment.

Offline folders means that a folder (could be home, in Windows is My 
Documents) is stored on a server but a cached copy is kept on the 
client/workstation. The user works with the cache and sees no difference.
On login and logout any changes are synchronized with the serverbased 
folder. If you are offline (travelling or server down) you will see no 
difference except an error when you log on or off that synch could not 
be done.

The advantage is of course that users files can be centrally backed up 
and if a computer crashes or gets stolen you simply configure a new one, 
"resync" and the user is all set to go. In Windows domains it works with 
"roaming profiles" meaning that if you log on to another workstation you 
will have access to your files but not your own desktop or configs.

I am looking for a way to implement this concept (minus the roaming 
profile if that is not possible) in an environment where the servers are 
either Windows or Linux (Ebox) and the clients also mixed Windows and 
Linux (Kubuntu hopefully). The organisation are moving away from 
Windows, are not going Vista but staying with XP and for new computers 
going LInux. But the offline folders is a security aspect for them, 
securing that users files gets backed up "automagically".

Any pointers, help, someone did something like this, assistance of any 
kind most welcome.

Sinclair