Alhough not obvious at first sight, it is possible to connect to two IM accounts at the same time, on the same network.
This method can be used for any protocol, and can enable you to connect to more than one IRC server at once. In this example, the ICQ protocol is used.
Use the right mouse button to drag the file to a blank space in the folder. Let go of the button, and a menu will pop up. Choose 'Copy here'.
Rename the new 'Copy of ICQ.dll' to 'ICQWork.dll' or something similar, but meaningful (to you).
Restart Miranda, and you will now see another ICQ protocol. You can configure this new protocol as usual, and enter your account details etc. in the options.
Also, to save confusion, you could use different icons for this protocol. Simply go tho Options->Contact List->Icons.