A very neat and simple program called
StarPatch.exe has been created by a guy who calls himself
Karl. By adding it to your Starcraft-directory, it will simply
run your Starcraft in a window mode. The resolution is 800*400 and it works fine - it's not updating itself to add information like Lasgo's OP3 does (»
news). However, it's not really fit for Battle.net and it's not working so good in the chat. Works fine as soon as you are in a game but being in a chat channel on Battle.net simply looks very weird, even though it's possible. Also,
do not move the window, because if you do, the cursor will hardly work at all.
The program is very, very useful for me as an administrator who doesn't play that much but does more of observing and chatting, so I can easily tab to windows and update articles and news. Check out the screenshot below and the discussion at SCLegacy.com about the program.
Links
SCLegacy.com - Source and more information