When using Safari on an iOS device, web pages that have mobile versions will display those versions, because they parse the user agent string sent by the browser. In general, this is a Good Thing, but you may want to see full web pages, and not the reduced mobile versions.
A blog post on the Technipages website explains a way to do this. It involves downloading a program called iBackupBot, altering a file in your iOS device's backup, then restoring it. It's a bit of work, but if you really want to view full web pages with an iOS device, you might want to try it out.
[kirkmc adds: I haven't tested this, and I don't do enough web browsing on my iOS devices to need this. It's true that some sites minimize their content when you access them from a mobile device, but in most cases, this isn't a problem for me.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20120323040047358