Well you can't hide your IP addiress, as it's the ISP that gives it to you !
You can change your mac address use ,SMAC , but that will do you little good either.
If you changed your IP then nothin will get to you.
I assume you get a IP everytime and are not using a static one, if you got a static one you could change it but then the wireless network won't know who you are, the same goes for the MAC address..
Sorry but there's not a lot you can do :-(
Well you could go wardirving :-)