IP problem ...

Not sure if this is the right place to post this. I got a laptop with WiFi and have connected it to a router so i can access the internet. The problem is I can't change my ip addy anymore. Is there a way I can either change or hide my IP so I can post on craigslist? I was manually changing it myself on my desktop, but I want to use my laptop now. Thanks!

Most wireless routers will allow you to change the setting through their web interface (ie:http://192.168.0.1 or http://192.168.1.1 or something else) or if that doesn't work then turn off your internet modem (unplug the power) then change the MAC address in the router (though the web interface) when changes are saved turn the modem on. That should do it.