I just googled for a iWork Keynote replacement for Ubuntu and found a post so wrong I can't resist to comment this. Unfortunately, it's in a read-only Froum, so I have to report here:
Pardon. It's neither impossible to mix more than one graphics environment in Ubuntu nor is there any restriction to port Mac software to Linux. Even a Cocoa-like graphics environment exists already: GNUstep.Originally Posted by gubemton
Even if there weren't GNUstep, it would still be possible to clone Keynote's appearance and behaviour with Gnome, Qt, whatever. The unique thing about Mac software isn't some hidden secret, it's about making the GUI simpler, yet more functional. Mac fans love the way Macs work, Linux fans obviously prefer less intuitive, more feature-rich (cluttered?) applications. That's all.
You're correct in iWork nor being open source, but the only reason for this is, Apple doesn't want to release it under such a license. That's all and there's nothing stopping an enthusiastic programmer from crafting something with an iWork-like user interface, reading and writing iWork-compatible files.So it's not that simple. And so iwork is not open source...