As I discussed yesterday, "Pokemon Black" and "White" starts players from scratch, preventing them from transferring pokemon from previous games until they complete the main "Black" and "White" adventure. In addition to that major shift, Nintendo is offering up new ways to interact with those you're playing with. One of these ways is video chat.
Apple's Facetime allows for folks to easily video chat with iPhones, iPod Touches and Macbooks. I wouldn't say that the video chat in "Pokemon Black" and "White" is as straight-forward, but it's pretty similar. Players will be able to video chat with approved friends (determined by "Black" and "White"-specific friend codes) over WiFi or local networks.
Functionally, "Pokemon" video chat is not nearly as smooth or clear as Apple's offering (the camera, for one thing, is lower resolution and really not designed for video), but for the basic thrill of seeing a fellow trainer's face, the experience is good enough.
Only owners of the DSi will be able to enjoy full video chat, since it's the only current Nintendo handheld with a camera built in. If you own an original DS or DS Lite, you'll still be able to chat with others, but it's limited to audio chat. If you're on a DS Lite, playing an owner of a DSi, you'll see their video, but they won't see yours.
If you're curious how this all looks in motion, you can catch a glimpse of the video chat feature in this Japanese TV show. The video chat segment begins about 35 seconds in.