Google Calendar.

Keeping track of appointments, meetings, and other important dates can be difficult to do. You could use a smartphone or PDA to assist you or maybe a paper daytimer. Any of those methods can be vary useful to help you stay afloat with your personal schedule.
Something new that I have been trying as of late is Google Calendar. I know some may shy away from posting all of your appointments to an online website, but I have found it quite convenient and a time saver as well. I'm already a Gmail user, so it's rather simple for me to adjust my schedule as I need to or put in new appointments from my emails as there is a link to Gmail in the upper left hand corner of my Gmail screen. At this point, it has replaced the Palm Desktop calendar software for me.
You can add appointments via your text message cable cellphone and also receive notification of an event from your cellphone. You can send a text message and receive that days list of appointments and events. This could be helpful for those who are a bit busy and forget about promised appointments to have an automatic reminder sent to their cellphone. Grant it, you better have a decent text message package with your cell company or you could wind up paying thru the nose.
For mobile device users, there is a free service called GooSync (they also have a paid yearly subscription version) that will sync your calendar with your mobile device. I use it on my Palm Lifedrive PDA. I can add appointments to my PDA and then later I can sync that appointment to Google calendar. Many cellphones are supported by these service as well, but you'll need a good data plan for your mobile device.
There is also support for multiple calendars (i.e. personal life, work, church events, etc.) It is also possible to set a calendar for public viewing and giving your church members an easy way to check out the church's calendar for the year or month. Having your church calendar readily available wherever you go would be very useful too. On the road or at home, you could easily make changes or add events with ease.
If you really think about it, having access to your email via Gmail and your calendar via Google Calendar would be an excellent way to stay productive in your ministry. Automatic reminders to your phone and you'll never miss another important meeting again! Well, unless you forget your phone...

BTW, if any of you would like a Gmail email address, please email me and I will send you an invitation to join Gmail. You could also use your cellphone to do the same thing by visiting www.gmail.com .