[RANT]
At so called helpers: excuse me but where was your opinion asked wether or not this should be made? Why turn this thread into a chat thread? And what does it matter what reasons the poster has for this..i for one can think of reasons why one would like to limit the messenger use of children. Can we please go back to only posting when you know the answer....i myself do not know wether a script like this would be possible but i still wanted to say something about the behaviour onhere.
[/RANT]
thedestroyer: i think you'd be better of looking for a parental control program or anything of the sorts that limits connection time to the internet (seeing as there are webmessengers too).
Edit: a well known Parental Control Program is
CyberPatrol.
/ 
