Ive just completed a remote access VPN using the Cisco client and a 1720VPN router. I cannot browse per se either. However, in my TCP/IP settings, I did specify my internal (private) WINS and DNS servers (different IPs). My main subnet is 192.168.0.xxx, and I use a range of 172.16.xx.xx for my local pool on the router. My workgroup name is the same as my main network.
What I CAN do is search for a computer by name through the tunnel. From what I can tell, all of the name resolution stuff is broadcast, and so it is blocked/dropped at the router. (right?) A specific search, however, has an originating, and thus a target, IP address. I can telnet/SSH/remote administrate like mad through the tunnel by IP address, and even ping by name using internal DNS, but I have, so far, had to use the Find Computer function (right-click Network Neighborhood) to access remote shared folders and printers.
On our site to site, we were able to get browsing working by setting one machine as the master browser for their subnet, and then diligently keeping an updated lmhosts file therein. It's a chore, but it cuts down on the service calls.
HTH
Nedstar1