Jay Freeman the creator of Cydia has released a new video recorder named Cycorder.
Currently the application doesn't not support audio; however this feature will be added in approximately one week's time.
Cycorder, unlike the iPhone Video Recorder, encodes in real time so there is no waiting once you stop recording. It utilitizes the maximum capabilities of the iPhone camera at 7-15 frames per second.
You can download and install Cycorder from Cydia.