I've lived with my BlackBerry for over a month now and I can honestly say that it's changed the way I work (and play). I made sure to snag one for my assistant who handles the elementary schools in our district, too. Because so much of the support I provide, as well as planning and coordination that I do is via email, having a phone that tells me every time I get an email and allows me to respond immediately has made for some very happy users and a very mobile me.
I don't know if I can say it's made my job easier; I feel a little bit hyperconnected and occasionally just have to turn the bloody thing off, especially in meetings that I actually want to be in. It has, however, made me significantly more effective in my job and made it a lot easier for me to work anywhere, whether that's at home, other schools, conferences, in my car (only when safely pulled over, of course), or wherever.
It's certainly made it easier for me to be visible and active in all of the schools. I'm home today working and writing, but it's a real non-issue; neither is going out for lunch. Much more than the average smart-phone, the BlackBerry has made my physical absence largely transparent to my users.
I've grown quite used to the keyboard, as well and have now installed Google's tools for the BlackBerry as well (Gmail, Maps that can access my phone's GPS, easy access to Google Docs, etc.). I sync my calendar easily with iCal on my Mac and Google Calendar for a backup and to provide office staff (and my wife) with access to my schedule. It's all seamless and tightly-integrated.
While RIM may be trying to enter the consumer space, their dominance in the business sector is well-deserved. Ed Tech folks, go get a BlackBerry if you don't already have one. Verizon and AT&T both have reasonably-priced plans with cheap phones for those of us in the public sector and educational markets.