How do I get online with my ipod touch via my siemens router. I get a message ...invalid argument. How do I know what the router password is?

You will need to loginto your siemens router to look at the wireless section to see the password ITS possible the password is written on the bottom of the router - some manufacturers do this for default password security
otherwise post back the exact model and we can look up the default access IP address and user/password