Sun Seeker and Theodolite
These two apps use augmented reality to layer information over the world as seen through the iPhone camera lens. Sun Seeker shows the solar path of the sun in the sky, winter and summer solstice paths, and provides date and time specific information about the sun. If I were buying a house, I'd want to know the sun exposure of the property. (I live for bright!) Gardeners will also find this tool handy.

Theodolite, pictured below, overlays a compass, GPS, map, zoom camera, and 2 axis inclinometer onto the world all around you. Use it for boating, hiking, surveying, etc. Save information overlaid on camera images for later use. (Sorry, I blurred the image from the camera lens by accidentally jerking the iPhone when I took the screen shot below.)

[Oops! I snuck in two applications in this section! This then leads me to a growing number of scientific data collection instruments that work together with the iPhone to collect data in the lab and in the field. (See this link at Pasco for an example.) Behavioral sciences are also included in this conversation. School psychologists, teachers, teacher aides, and even parents can use Behavior Tracker Pro to support the behavioral treatment plans for children with Autism and behavior disorders. This section alone could turn into an entire post. And then there are applications for classroom observations.... I think I'll just have to revisit all of this in a stocking stuffer post.]

Navigon

I had a difficult time deciding which realtime navigation GPS to purchase for my iPhone and finally decided on Navigon North America, and Europe--two separate applications. I also purchased the TomTom Navigation car kit, which works beautifully with the Navigon software and significantly improves reception of the GPS signal. (Apparently the GPS signal is very week compared to radio/TV and is independent of the application or phone. The car kit has an improved antennae system.) This application has helped me get on location twice when the navigation system in the rental car had "issues." The above screen shot was from a recent trip to Cashel while in Ireland.

Yelp!

Having lived in LA for less than 2 years, I still have no idea where to go for this, that and the other. Yelp has been a fantastic resource! No matter where I am, I can locate restaurants (or any number of businesses) near where I happen to be. I found my optometrist through Yelp's customer recommendations, a cool locally owned bookstore, numerous restaurants, a framing store, etc. I hear rumors Google is in final discussion with Yelp! for a purchase rumored at about $500,000,000. The Yelp! community is large, younger, and vibrant.

WorldCard

I just found this little application. Take a picture of a business card with your iPhone. Using OCR (Optical Character Recognition) the application finds the information on the card, gives you the option to edit and approve it, and then uploads the information as a contact to your address book. Nice! I'd say it's about 90% accurate, and again, anything that can save squinting at tiny letters and numbers on a business card and trying to type them on the iPhone's small keyboard is a huge help. The application is available in several different languages.