Basically, we're talking about a $10 application(currently available in Apple's App Store) that allows your iPhone to access media files available on a PC, including videos, music, live TV and live streaming from a webcam. Even better, OrbLive works via any available data network, so you don't have to worry about not having Wi-Fi, as long as you got some 2G or 3G<-180x150 Small Rectangle - right-> connection around you can use.
The funny part is that not so long ago, OrbLive required users to jailbreak their phones, since the original version was written before the App Store became available. Now, OrbLive 2.0 is ready to be grabbed from the App Store for a mere 10 bucks, as I was just saying.
At last, if you're not one of those who buy first and ask questions later, I suggest you to grab the free trial that is limited to playing three random titles of each media type, by using the same App Store link above. Enjoy! ;)