connecting to the internet on my psp

Well when i try to connect to my wireless connection it says obtaining IP address for 30 seconds then says theres an error and connecting to the Ip address timed out

anyone know whats wrong or what i have to do

the password key in the router?

 sorry i don't know that much about that stuff can some one explain

does entering an IP adress manualy do anything and how could i find it out

how do you do that