Disclaimer: Brand new to iOS dev. Go easy on me.
Got a funny situation in Xcode 4.5. My Size Inspector looks like this:
You have Autolayout enabled for the view, turn that off and it will look like what you expect. Autolayout is a new feature for iOS6 that allows more granular control of how things are laid out, and really enhances what was previously available via the struts and sprints via autoresizing masks.
To turn if off, open the Identify Inspector, and uncheck "Use Autolayout"