XP-erience.org has posted an Internet Speedup and Security guide

If you have a LAN at home, be extra careful about some settings regarding NetBIOS (Tcp/IP NetBIOS Helper Service (an NT based OS service) & also NetBIOS over Tcp/IP in your WINS properties) & Client For Microsoft Networks (needed to change workgroup name & machine name and other network functions) as well as some of the Port filtrations, since some ports are used by NetBIOS (135-139), and also some of the registry hacks for security.

Read more