The
December release of UDK beta now contains support for Apple's iOS which means you can use the development kit to make game content for iPods, iPhones and iPads (as well as standard Mac OS?). If you want more on the tech skinny for what this means visit the official site at
http://www.udk.com.
Keep in mind that if you do use UDK for iPhone/iPad/iPod game/media development you will be (currently are) required to buy a
Apple Developers Program license, which currently starts at
$99US for the
iOS Developers Program. Your apps and/or games can only be sold and distributed through AppStore and Apple takes a (minimum?)
30% commission on sales for doing so.
In addition to Apples development fees,
UDK also carries with it similar licencing conditions; an up-front fee of
$99US and
25% royalty on revenue above
$5000US is applicable, assuming you're making a game for distribution NB. it's not clear if the up-front fee is a one off payment on registering the licence, it's assumed it is. There are different license structures depending on what you're doing so be sure to read the terms and conditions carefully.
As you can see, for individual devs there's a reasonable amount of money needed to get started, and that's not necessarily inclusive of your apps being approved and accepted by Apple for sale in App Store (I know a few indie devs that have had apps refused for what seem rather arbitrary reason, well as best as they can figure out as Apple doesn't always appear forthcoming with their reasons for rejection); if you can spread the costs all the better.