The external iSight camera was actually better than the built-in iSight, with a more light-sensitive camera, autofocusing lens, as well as a high-quality built-in microphone. I've got two of those old iSight cameras. They'd fetch a good price on eBay.
Once the external iSight camera was quietly discontinued in late 2006, the video capabilities of iChat, and of other applications that could use the camera, were limited to iMac and notebook users. Everyone else... well, tough cookies.
Ever since 2005, the Internet has swarmed with rumors that Apple would update its Cinema Display line of external monitors with an iMac/MacBook style iSight camera and microphone combo. That's finally come true. Well, sort of.
On Oct. 14, Apple announced a 24-inch "LED Cinema Display," an update of its Cinema Display line. Marketed as being an accessory for MacBook, MacBook Pro and MacBook Air notebooks, the new monitor includes a notebook battery charger, three USB 2.0 ports  and an iSight camera, microphone and speakers.
The good news is that the LED Cinema Display finally started shipping, and is available now for $899.
(The "LED" part of the name means that low-voltage light-emitting diodes, instead of fluorescent light bulbs, provide the lighting source for the screen. The benefit is both lower power consumption and a greener footprint, since the fluorescent bulbs contained hard-to-recycle mercury and arsenic.)
The bad news is that it's, well, an accessory only for Apple's latest MacBook, MacBook Pro and MacBook Air computers  also announced in October  which use the Apple's new "Mini DisplayPort" video connector. Owners of older Apple notebooks  and desktops  need not apply.
Perhaps a third-party hardware supplier will offer an adapter that will allow the new LED Cinema Display to work with older Macs with DVI video connectors. Until then, most of us can only iSigh.