You always have to change Network Settings like IP / Wins / DNS
Configuration /DHCP.
The "netsh" Utility gives you the possibility to "dump" all settings into a
file, that you can later use to restore your complete Network settings.
To Save the current Settings:
netsh -c interface dump >networksetting.txt
You can then create a dump file for every Network that you use.
To Load the Settings again:
netsh -f networksetting.txt
In this way you can easily switch between different Configuration Sets.
http://www.sunbelt-software.com/ntsysadmin_list_charter.htm