QuickTime question..

I need to create a video that records multiple channels. Can QuickTime do this without additional software, or do I need to download software like soundFlower?

That would likely depend on how you actually plan to input and "record" the data. A QT file may contain up to 99 tracks of audio, video, text, image, or other data. Each audio track, depending on the compression format and/or settings used, may be in mono, stereo, or surround sound channels and each track channel can be independently assigned to a specific speaker/use as seen here using QT 7 Pro features:

However, most people would probably not consider the QT 7 or QX apps to be software Digital Audio Workstations in the same sense as GarageBand (or other, more advanced and more expensive dedicated software packages).