The iPhone and iPod Touch version of Assassin's Creed: Altair's Chronicles has gone on sale for GBP 5.99 / USD 9.99.
It's available on the iTunes App Store right now, and weighs in at around 140MB.
We tried downloading it this morning for a quick go, but our not-at-all-jailbroken iPhone evidently needs a firmware update to run it, so beware of that.
According to Ubisoft and developer Gameloft, the iPhone version is a spruced-up version of the DS game of the same name.
Check out our Assassin's Creed: Altair's Chronicles iPhone gallery to see how it looks.