keyboard activity logging in FreeBSD

[Ganbold]

Hi,

I would like to log all keyboard activities in all ttys in my FreeBSD 5.2 box.
Is there anyway to do it? I read the watch man page and it seems like
I should run watch with tty as many times as number of ttys. Am I right?
Also is it possible to do the log in invisible way?
The main reason is to log all commands typed in shell and tty and send the 
log to the remote server.
How can I accomplish that?
Any helps and directions are greatly appreciated.

thanks in advance,

Ganbold