Long a productivity staple for the iPad, Apple has downsized its office app suite for the small screen today with the announcement that Pages, Numbers, and Keynote are all available for the iPhone 4 and 3GS (along with the 3rd- and 4th-generation iPod touch). As before, the iWork apps run $9.99 each -- not exactly pocket change if you're in the market for all three, though existing owners will be able to upgrade to the universal versions that run on both their iPad and iPhone for free. Clearly, this is a shot across the bow of the well-entrenched mobile productivity players like Quickoffice who've been offering these apps for years, so it'll be interesting to see how much market share Apple's ultimately able to capture.