i am developing an application in which i am trying to record a video using AVCaptureSession class...i came across a few good tutorials like this one
Check out the sample code from the WWDC 2010 http://developer.apple.com/videos/wwdc/2010/ for example the AVCamDemo.
Login to your iPhone developer account (the box with "Download WWDC 2010 Session Videos for Free") then you see a new page and there you can click on "View in iTunes" and then in iTunes(!) you get the link to the WWDC 2010 example source code... or you can try the link
http://connect.apple.com/cgi-bin/WebObjects/MemberSite.woa/wa/getSoftware?code=y&source=x&bundleID=20645
but to download the source code you must also login to your developer account.