What do you mean by 'spy' software? You want to spy on someone's computer?
If so, that's hacking. Under the new 9/11 laws, you could be sent for life imprisionment for any form of hacking. Are you sure you want this "spy" software now?
Also this thread would be closed for promoting illegal activity.
If you own the computer, then it is perfectly legal to remotely spy on a person using it. There are many programs that allow you to do it... if you are looking for freeware you might want to try
C|Net Downloads. Anything you get from C|Net is
not remotely deployable.
Anything that is remotely deployable (without the owner's consent via EULA) is considered a Trojan, and is illegal.