[rant mode]
Obviously this can't be done on an Ipad (unless jailbroken)
It is un-necessary to utter the (technically incorrect) statement above when you have to ask......
how much work would it be to write a little app
If I had a penny for every time someone asked me "how much effort/time/money would it be to write/change a little X for/on Y" ....
Since you probably don't know how to write Objective-C (assumption made because if you did, you would know the answer to your question), its irrelevant whether or not you (or someone else) can write something for the iPhone.
[/rant mode]
But because I'm feeling nice today
, the answer to your question is....
On linux or windows where you can run high level scripting languages (php,perl,ksh,batch files), its easy as pie if you've got the right sort of data feed (easier on *nix/*nux than windows, but I digress)..... but on something like an iPod/iPad where you need a lower level compiled language.... unless you know how to write it yourself, you're going to have to rely on someone else's skills and time.... which will probably cost you some money unless you meet someone down the pub who's day job involves a bit of programming.
It's not just about writing something... it's about writing something stable, bug-free, that handles exceptions well and is programmed in such a way that it parses your data in a correct and efficient manner (and ideally displays it in a nice pretty output format). So someone's mate who's just worked his way through "<some programming language> for Dummies" is unlikely to do a good job.