Is there an easy way for novice users to change their user agent string so that they can use websites that say "only works with Internet explorer" and won't let them log in unless they use IE? So they can use their iPhone/iPad with that website?
Many websites that are "IE only" are such because they use ActiveX controls. You can spoof your user agent, but it's not going to magically make the site work if it requires something in IE that Safari/WebKit doesn't provide.
If the device happens to be jailbroken, install User Agent Faker from Cydia. This is what I use when I happen across a site I want to force into regular browser mode instead of being routed to a mobile site without asking my preference.