AntLog is a spreadsheet template for OpenOffice.org, with macros built in to handle events from 16 to 48 entrants.
One other handy feature is that it tracks which order the fights happen in - very useful information when trying to edit the video!
The reasons for using OpenOffice rather than Excel are as follow (you may choose to disagree with me):
OpenOffice.org is free
OpenOffice.org is available for Windows, Mac and Linux
Not everyone has MS Office and not everyone runs Windows
I couldn't figure out how to get Excel to track the order in which the fights happen.
If you have OpenOffice.org, please download AntLog and the instruction sheet and have a play with it. This is the first release so there may well be a few "features"

http://garya.org.uk/antweight-robots
mirror at:
http://homepage.ntlworld.com/g0xan/robots/
The printable charts for those that don't wish to trust electrons are available here
Edit: Updated website link