I depends on what level of control over your server that you want other people to have. The ultimate is having the rcon password. That allows people who have it to kick players, ban players, change the map, gametype, timelimits, fraglimits, etc., enable cheats or even shut down the server. That may or may not be more control than you want to give people.
If you want to limit what other "subadmins" are able to do on your server while retaining rcon control for yourself, you need an "admin mod". There are many out there, and they all have their fans. In my opinion, only two are worth considering: xMod2.3 and Jedi Academy Reloaded.
xMod
http://www.cat5camp.com/xmod2/)
Jedi Academy Reloaded
http://jamod.jk2files.com/index1.html)
Both allow you to control exactly what your subadmins can and can't do. Both have unique and cool features, check them both out and try both of them.