Looking for iPad’s User Agent String? It’s here:

Mozilla/5.0(iPad; U; CPU iPhone OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B314 Safari/531.21.10

To change Your browsers “Agent String”, You can use User Agent Switcher Extension For Firefox or “Other…” from Safari’s Developer menu.