Well depends on which services the network uses, but the command is usually to do with NickServ and is similar to this:
/msg NickServ Identify YourPasswordHere
As for how to make it automatic, you can use mIRC's perform function, which you can find under
mIRC Options (press Alt+O ;))
It's under the
Connections ---> Options. Just click the button marked
Perform....
Now click the
Add button, scroll down(or up) until you find the server, select it, press
OK and in the
Preform commands box type the above command (/msg NickServ Identify YourPassword). Click on the tick box named
Enable perform on connect to mark it with a tick.
Hope that helps
