I've used Perl to turn a CSV file into a .plist (which the iPhone can load much more easily). So, sure. You won't be programming on the iPhone in it (unless, as mentioned, you jailbreak your phone), but honestly you probably don't want to.

The support for hooking into the iPhone OS is not going to be there in Perl, and putting it together will use up cycles that you;d be better off investing in learning Objective-C and Cocoa Touch.

I'd point out that there are several applications I know of that do use interpreters behind the scenes - Rjdj uses the Pure Data music programming language, and the Smule guys use a built-for-the-iPhone port of ChucK (another music language) for their software.

So it's not Thou Shalt Not Use Interpreters, it's Thou Shalt Not Ship A Product That Lets People Do Whatever Random Programming They Want On The Phone.