I saw this thing at Frys a USB to VGA connection which is great for multiple screens. The problem is does this device work for apple or are there any mac friendly devices?
Check this out first. It's a similar product from Gefen that is a USB to DVI adapter. It doesn't work well at all mostly because it can't go higher than a 60 hz refresh rate at resolutions higher than 800 by 600. I really would stay away from it if I were you. Is there a reason you can't use a VGA port? If your Mac doesn't have a VGA port, then use one of the following. The links are to the Apple made versions but obviously third party versions are much cheaper.
Reason is I have two monitors, my second monitor is more for browsers, text and folders. I want to make this monitor connected via USB and connect my tv as third monitor for itunes, movies etc.