I'm not 100% certain this works with Windows XP, but it works in Windows 2000 and I would assume that it still works in Windows XP. The network I work on still has primarily Win2K workstations so I don't really have a WinXP station to test it with.
Shutting off NetBT greatly reduces the network's browsing functionality because the Computer Browser?the service manifested in Network Neighborhood, My Network Places, and the Net View command?sits atop NetBIOS.
To disable NetBT manually, right-click My Network Places and choose Properties to display the computer's TCP/IP properties. (You can use DHCP to disable NetBT on a system, but that process requires a fairly lengthy explanation, and this way is much easier if you only need to configure a few computers.) In the Network and Dial-up Connections window, you'll see an object for each network card on your system. Right-click the network card for which you want to disable NetBT, then choose Properties. On the Properties page, double-click the Internet Protocol (TCP/IP) object, then click Advanced on the Internet Protocol (TCP/IP) Properties page. Click the WINS tab, then click the Disable NetBIOS over TCP/IP radio button. Clear the Enable LMHOSTS lookup check box, then click OK until you've closed the pages. To verify that you've killed NetBT, you can type
If a user happens to know the name of the other computers on the network, they can use the Net View command to list its shares without NetBT's help using a command like this one:
net view bigserver.acme.com
to list its shares. But that's the only way anyone would be able to browse any resources on the local network.
edit: One additional bit of info to add to those instructions...
After you disable NetBT, you can shut down the Computer Browser service to recover some memory and simplify your system's software. The Computer Browser service will eventually stop itself if it is not able to locate the NetBT service if you don't stop it manually