In your browser go to "about:config"
Right click and choose "New" -> "String"
The name should be:
Mozilla/5.0 (Linux; U; Android 2.2.1; en-ca; LG-P505R Build/FRG83) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1
You don't even have to restart to make this work.