question about locale

sorry if this is a dumb question but i am using a non rooted MyTouch 3G and attempting to use locale. now for when i am home i put in the location and to have wifi on but i also have a default situation and when that is on, it uses that instead of the home situation. to make the home situation work i have to turn off the default situtaion but the problem is, when i am not home, the wifi remains to be on and wastes my batery. i know that i can manually turn it off but i usually do not remember and this would be easier if i could get the locale to work. any help?