How to access internet on PsP?

My school has wifi, i dont know the ssid for the school.

Keeping in mind they wont tell us how can i access the interent from school on my PsP or how can i find out the ssid neccessary for internet access?

well....
chances are they've encrypted the connection as well

non-broadcasting of the SSID is not a particularly good security measure
all you need is access to a machine already on the wireless network and write the SSID down

for gaining access to any WEP / WPA key, you will have to get more inventive