Re:Instead of asking Slashdot (Score 1)

I agree completely with this approach. The feedback from your users could provide you the insight on technical aspects not thought of before.

If you do decide to take the plunge, googling transition to open office yields a few articles:

Author Solveig Haugland offers a "virtual guide" to switching
http://www.fanaticattack.com/2008/switching-office-suites-from-microsoft-office-to-openofficeorg.html
Difference between Impress and Powerpoint
http://www.linux.com/articles/40736
Five principles of a successful OO transition
http://www.k12opentech.org/solveig-haugland/2008/02/24/five-principles-successful-openofficeorg-transition

There is probably a slew of articles on this topic out there, just do the research.