Windows 2000 & XP machines delay as long as 30 seconds when you try to view shared files across a network because Windows is using the extra time to search the remote computer for any Scheduled Tasks. Here's how to prevent this remote search for Scheduled Tasks:
Open up the Registry and go to :

HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Explorer/RemoteComputer/NameSpace

Under that branch, select the key :

{D6277990-4C6A-11CF-8D87-00AA0060F5BF}

and delete it.

If you like you may want to export the exact branch so that you can restore the key if necessary. This fix is so effective that it doesn't require a reboot and you can almost immediately determine yourself how much it speeds up your browsing processes.