Different internet connections do often require completely different proxy server settings and it's a real pain to change them manually. IE7Pro Proxy Switcher lets you manage and switch between multiple proxy configurations quickly and easily.
Proxy Switcher Tutorial
Manage Proxy List
There are three way to add a new proxy to IE7Pro Proxy List:
1.Internet Explorer "Proxy server" setting
2.IE7Pro "preference" - "Settings" - "Proxy" . Check the "Use Proxy(Toggle by Ctrl+F9)" and add new proxy and port , eg. 206.11.30.2:8080.