changing proxys when in diffirent networks auto?

[_Jimlad_]

is there anyway for my proxy settings to change in preferably firefox or if not ie8 when i change network location. at home i leave my proxy on auto detect, and when i'm at work i have to enter a 192.168... blah blah blah, at the moment i have to change each and every time other wise i have no web access, anyway i can change this ? i'm using full windows 7 pro.

 

[_Jimlad_]

i can't see a way of doing it, i know you can in apples (dam them) - its not much of a hassle but shame if it can't be done as it would be handy