This is an especially important problem around the holidays when lots of e-mail with attachments that are both naughty and nice get forwarded around.
I don't know of any home software app that can monitor all installations, via the Internet or otherwise. However, if you have Windows XP, you have a great way to let your family enjoy all their favorite programs while you control the installation thereof.
In Windows XP Home Edition, you'll want to set up your login (and only yours) as the computer administrator and limit other users such that they can either install or not install programs and software--sorry, there's no middle ground.
Here's how to get to the User Accounts tool. You'll want to designate yourself an administrator and make sure no one else is.
Go to Start.
Choose Settings.
Choose Control Panel.
Double-click User Accounts.
Select Change An Account in the Pick A Task list box.
Click the account you want to change.
Click "Change the account type" to increase or decrease

the user's rights on the computer.
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