I have found some great tools so far to use for teaching with the iPhone.
Lets start with the basics - Software to work with Google.
Google Earth - No explanation needed.
Google Mobile App (Free) - Gives you quick access to several Google Features. Gmail, Calendar, Docs, Reader, Talk, Goog-411, News, Notebook (for now), Photos (Picasa), orkut, Translate, Maps, Youtube, Earth, and Blogger. It will even let you set up for multiple domains.
CalenGoo (Paid) - A great way to sync with your Google Calendar. Syncs both ways. The Publisher is extremly responsive to questions and suggestions.
MiGhtyDocs (Free) - This app will let you cache your Google Docs to your iPhone so you can use them even when you don't have service.
Next, lets look at apps to help directly in the classroom.
i-Clicker PowerPoint Remote (Free/Paid) - Just like it sounds a remote app to run your PowerPoint. You will have to install an app on your computer, so you will need admin rights or have a good relationship with your IT person at school. The app lets you view the current slide, the next slide or notes that you have saved. It has a timer to help keep you on task, a forward button a back button, and a jump to slide# feature. There are two versions available, the full paid version and the lite version (limits you to 15 slides).
LabTimer (Free) - Simple little app that will allow multiple timers at once. Count up or count down.
a2zPro (Free) - A conversion app with plenty of options, such as Distance, Energy, Length, Pressure, Blood Sugar, Speed, etc...
WordPress (Free) - Simple tool to update your your WordPress Blog. Allows you to save drafts locally to your iPhone before posting. If I could change one thing, I would like to be able to see drafts that are saved on the WordPress website.
Animoto (Free) - This is very similar to the Animoto website that lets you make a quick video. Pick a song and upload some pictures and let it make the video.
Locly (Free) - Great tool when traveling with students. It finds your location and then lets you choose what you are looking for; restaurants, museums, taxis, banks, etc...
Evernote (Free) - One of the best note taking tools on the Internet and the iPhone makes it even more usable.
Speed Dial #1, #2, #3, #4 (Free) - Simple apps to do just what the title says.
SuperDial (Free) - App to make a favorites list to with pictures.
Twitteriffic (Free) - Great free Twitter app for the iPhone. Hopefully the next update will have the ability to retweet.
Twitterlink (Free) - This app will allow you to create a bookmark in Safari on the iPhone which will create a shortened URL for your tweet.
ResponseWare (Free/Paid) - Free to download but you need to pay to register with TurningPoint so it can be used. Those of you that could get some money to buy a class set of iPod Touches would love this app. Allows individuals to answer questions with the TurningPoint response software.
These are apps that I have used and I prefer. Some of you might find an app that you would prefer over the ones I have listed. This is one of the great things about the app store; there are plenty of alternatives.
Please leave comments if you might prefer a different app, or please let me know if I have missed any.