This workflow may be better titled "getting around Apple's QuickTime Player X limitations" in a nod to a recent Bit of Tech review that notes the new version of QuickTime, named QuickTime X and completely rewritten for Intel Macs, is a bit lacking when compared to the Pro options in the old QuickTime Player 7.
In fact, compared to QT Player 7's Pro options, such as aggregating movie clips together (appending a second clip on to the end of another in basic "cuts only" editing) and the extensive list of export options, the QuickTime X player is a step backwards.
Fortunately, for those who upgraded to Snow Leopard (10.6) from the Leopard (10.5) operating system, Apple left QuickTime Player 7 intact, including the Pro version, if Pro was already installed on the old Leopard system. Whether this is an oversight, or a nod to the fact that QuickTime X was shipped too early, the fact that QuickTime Player 7 is still functional is welcome news.
The work-around workflow, then, for aggregating clips and exporting content to more than just an Apple TV, iPhone, iPod or Macintosh computer, is to use QuickTime Player 7 with Pro options.
If you've already upgraded and didn't have Pro installed at the time, you'll need to downgrade to Leopard, or find an alternate paid application, until such a time as Apple chooses to add back the functionality it stripped from QuickTime Player.