Here’s how you change the title text that appears at the top of the Messenger window. By default, this is “Yahoo! Messenger”, followed by your status. Simply edit the ymsgr.ini file, which you will find in the same folder as the Messenger program, in your Program Files folder. Locate the file and open it in Notepad. Then, at the end, add the following:
Here, “YOUR TEXT” is whatever you want in the title bar. Save the file and close Messenger. When you restart it you will see your text in the title bar.