In Windows 2000 and XP both when you're browsing a network windows by default automatically searches for scheduled tasks while you're browsing a computer. This can add up to a 30 second delay. Make sure you backup your registry before doing this since any registry changes have the potential to cause problems and even break stuff!

1. Open up regedit.
2. Browse to HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/Current Version/Explorer/RemoteComputer/NameSpace.
3. Find a key named {D6277990-4C6A-11CF-8D87-00AA0060F5BF}.
4. Right click on it and delete it.

Here's an image for those that may need it:

 
Let me know your experiences with this tweak... It works here on my XP machine.