I gotta say that the most useful app that I have is called "Informant". I had to play a bunch of games with my computer at work to make it do what I wanted it to... but that is my works' fault , and not the app. If your work is like mine, and they do not allow a mobile to have direct connection to the Outlook Exchange Server, that can suck. You want to have your work schedule on your cool hand held device, cause you are a tech whore like me....
No worries. Get Informant. Then head over to Google, and get their Outlook Exchange/Google Calendar synch application and download it. You can put it on your computer that is inside the network, and have it update your Google Calendar with your work info. Now just connect your Informant to Google Calendar. I have it synch"ing" in both directions so I can update from the ipod touch, and that is working well. That way I can keep up to date in all directions. Luv it.
It also has a to do list, which I use a little, but not a ton.