how do i find what is my wep number or pass???

[moh230]

ok iam trying to connect my wireless modem connection to my psp the psp shows the connection that i have but it needs an WEP code and i dont know how i can find it i heard that when you reset your modem you get to choose the wep or something like that so can any one tell me where to get it plzz i need this badly lol cuz i cant play mlb 08 online xD
oh yea and when i got the modem the wep code was already set so i aint stealin it from someone else lol its myn