I've watched the WWDC 2008 Keynote Address and it gets interesting from about twenty minutes in when new iPhone apps are presented. The two demos I really liked were:

• Finding out where friends are and what they're doing with Loopt
• Retrieving local news with the Associated Press

They're interesting because they rely on geolocation to provide relevant information which is a really useful implementation of the technology. The functionality of the iPhone looked seamless across the board; in fact the whole Keynote with its map of the iPhone's coming world domination was extremely slick. Worth a look.