How to send a message to network computersThere are two general ways to send a message to network computer(s),
Method 1. Net send command line provided by Microsoft.
Step 1. Gather the names of the computers in your local or company network.
Step 2. Click Windows Start>>Programs>>Accessories>>Command prompt to open a command line window.
Step 3. Type the Net Send syntax in following FORMAT:
net send {name | * | /domain [: name] | /users} message
Press the "enter" key to run the command.

Advantages and disadvantages of Net Send:
It’s free, but there is a limitation of message LENGTH, spam or useless information maybe distributed on your network, and the network users cannot reply to your message.

Method 2, Use a LAN messenger
Step 1. Before implement the LAN messenger to your company or private network, you can do a search for the advantage and disadvantage of Net send as compared to a LAN messenger from the page http://www.bigantsoft.com/net_send.html

Step 2. You can find a LAN message through Google search or refer to a professional shareware collection website.

Step 3. Compare the features and PRICE of the LAN messenger, download a free trial to see if the LAN messenger fulfills your requirements.

Advantages and disadvantages of use a LAN messenger to send message to network user:
LAN messenger encrypts all data transmitted through your company network. You can send/receive message even files and folders. The GUI on client side is more user-friendly and functional. Most specialized LAN messenger are shareware, so extra budget for implement a LAN messenger will be considered. For MEDIUM and large company, IBM Lotus Sametime and Microsoft LCS will be a good choice, for small and medium company, you can get a try with Pidgin, BigAnt LAN messenger, Jabber.
the "Windows Messenger" Service is disabled by default in XP SP3, Vista, and Windows 7 so net send won't work with those as recipients.Quote from: BC_Programmer on September 15, 2009, 06:27:47 AM

the "Windows Messenger" Service is disabled by default in XP SP3, Vista, and Windows 7 so net send won't work with those as recipients.