Looking for client/server apps that support CIFS (Common Internet File System)

We want to implement CIFS  on our win 2003 server that is in
collocation.  It is a file server and a terminal server.

We used to be able to pull off file from the shared drive when it was
our in-house fileserver via SMB.  Since we moved it to co-lo we can't
do that anymore.  We lost our S drive.  the Shared folders we all use.

Is there some inexpensive software using this new CIFS proposal (or ay
other protocol that is safe and easily routable over the internet)
that we can download to the server to each XP client to make it like
the old days when we could easily get to our S drive as if it was like
any other attached storage?

I know we can setup a VPN tunnel and do it, but i want to avoid that at all costs.

thanx in advnce