Using NET SEND Command...

Is someone like administrator can detects me when I'm send msg to my friend using "net send" command via nework?

Depends, I know at least there is a log on the receiving computer, and most likely the sending computer. I'm sure there can be some sort of central logging setup for it. The log on the receiving computer will show up in the event viewer of administrator tools, and with an organized ip/computer name assignment, an admin can easily track you down. It also says your username I believe, so if you have a specified account, be aware. I don't think you'll get in too much trouble for a first offense, but it's probably a good idea to just not do it.

why talk to them that way?

you can use "winchat" to talk to someone on another PC (if the admin hasn't disabled it)

start, run, winchat

net send has too much room for error. one wrong command and everyone can see your message.

LOL
I got caught using that command 2 years ago they ended up disabling it. They can monitor it but they don't at schools the only reason I got caught is because it is slow and the kid raised his hand for help 2 seconds after I hit enter and it popped up on his screen when the teacher was standing there. She founf out it was me because it said the computer name on the damn thing. :( http://www.antionline.com/images/ieimages/2004/02/1.gif