I've been using my N900 for a while, but i never found an answer to this:
Do we have some sort of an app or a script that will allow us to connect to a certain Wifi SSID as soon as it is in range?

There are only 2 wifi connections i use, one at home and one at the uni.

Note that i know that if i enable 'Connect Automatically' it will do so, but at my uni there are multiple connection at each loaction but i can only access one, so it tries the first one on the list and fails.