Unlike VNC clients where you actually control the desktop from the iPhone, Soonr is offering a web-based AJAX web app that lets you access parts of your desktop instead. What's better about this approach is that the UI is customized for the iPhone display, so there's little scrolling around to find the thing you want.
With Soonr, you can view a bunch of doc types (over 40), including PDF, Word and Excel, but they're re-rendered onto the iPhone by Soonr instead of using the iPhone's default rendering (because it can't). There's Microsoft Outlook integration as well, and even Skype text and voice chat. The voice chat isn't quite free, since it uses the Skype-out dialing to hook your iPhone call into the Skype call, but for international calls it's probably much cheaper than actually dialing the number on your phone. [Soonr]