Steve Jobs only explained a few of iOS4's 1,500 new features at the recent WWDC keynote, so we can probably excuse him for not mentioning what appears to be direct Facebook video uploading in the new version of the iPhone OS. 9to5mac spotted a Facebook export preset record in the latest iOS4 code, which would seemingly add a "Send to Facebook" option to the current video sharing choices.
According to the preset, video uploaded to Facebook won't be available in the same 720p HD that the iPhone 4 is capable of recording. Instead it can either be up to 480 pixels high or 480 pixels wide, at a maximum frame rate of 30fps.
iOS4 is due to be released on June 21st, and will be available for iPhone 3G, 3GS and (second-gen onward) iPod touch owners. However out of those only the 3GS can record video. More details on the new platform here.