How do I import photos from my iPhone when using iPhoto in full screen mode on Lion?
Use iCloud’s Photo Stream feature. As you noticed, you can’t access an iOS camera device connected via USB from iPhoto in full screen mode (in fact, iPhoto will leave full screen mode when you connect such a device). Photo Stream however is available in full screen mode (in the “All Albums” section). You can even setup iPhoto to automatically import photos from Photo Stream (sorry for the German screenshot, but you’ll get the idea).