Price: Free, but requires $25 "Pro" accountFrom: Remember the Milk Pty.

is a to-do productivity application that can get around one of the big weaknesses of most to-do lists -- you have to look at them. I know that's a problem for me. For example, iCal can send you e-mail or desktop note alerts, which helps -- but it only works if you are at your desk.

This app will display an alert at user-defined times before a task must be done. The alert will arrive via IM, e-mail or SMS. It works with Google Calendar, and you can manage tasks even if you're offline and you can share them, as well. It's like the way your mom would remind you to do homework when you were a kid.

These five are just the tip of the iceberg, given the thousands of apps available already and the countless others in the works. It took a little while after the initial APIs were released for developers to start really taking advantage of the iPhone's initial features, like multitouch functionality. We'll be seeing more as time goes on, especially since by most metrics, the adoption rate has been fabulous for the new operating system -- more so with iPhones, where it's free, than on the iPod Touch, for which there is a $9.95 charge because of the way Apple accounts for revenue.