I believe I have read in the past that mapping a drive over an ssh tunnel is not possible. However, if you use UltraVNC on both ends of the connection you can probably use its file transfer option.

no, it's easy enough, done it a few times for smb / cifs drives at least. would be harder with nfs using portmapping and such.

Is there a guide you can point me to? The ones I have seen on Google talk about uninstalling the File and Print Sharing feature in Windows. I find that a little odd. How will this affect my file and print sharing with other computers in my LAN?

well smb shares are just port 445, if that's the port being tunnelled, then that's what you'll connect to at the other side. i assume there are complications with netbios logons and such, but basic stuff is simple.

I am using putty to create a tunnel to my samba machine at home

source port: 139
destination: localhost:139

on my home samba machine I have /shares folder - make sure the following ports are open on your linux machine .
netbios-ns 137/udp # NETBIOS Name Service
netbios-dgm 138/udp # NETBIOS Datagram Service
netbios-ssn 139/tcp # NETBIOS Session Service
microsoft-ds 445/tcp # Microsoft-DS

now once you login with putty to ur home machine run netstat -an and u should see:
tcp 0 0 0.0.0.0:139 0.0.0.0:* LISTEN

on ur work machine map a netwrok drive
drive : Q
folder: \\127.0.0.1\shares
connect using a different user:
username: the samba user name
password is the samba user password