IP Manager 2.4

the author of this app says:

IP Manager takes the hassle out of using multiple networks. You can change between DHCP or a list of static addresses at startup.

The program keeps a database of all your settings. When you run the program, it will change your IP address, Subnet Mask, Default Gateway, DNS, WINS and your proxy settings for Internet Explorer.

The program also comes with a MS Access database to let you make your own network and proxy databases. Even if you delete a partnership, IP Manager allows you to switch back to the deleted partnership.