Over on the Citrix Blog, the rhetorical question of the day is "What's the coolest app that doesn't work on the iPhone …. yet ?"
Apparently, an iPhone port of Citrix Receiver is in the works (no release date set), which will "bring the world of millions of Windows apps and developers to the iPhone." They're currently looking for apps that don't run natively on the iPhone, but could be hosted on XenApp and delivered to the iPhone.
Some proposed apps include Web sites that require flash, medical apps, Web apps that require Internet Explorer, and even Cut & Paste (albeit within Citrix sessions).