Dr. Greg Little sums things up nicely:

…in a 2006 and 2007 book, The Cygnus Mystery, science writer Andrew Collins showed how the three crossbar stars of the northern constellation of Cygnus actually fit the three pyramids better than Orion’s Belt. In fact, the fitting of Cygnus onto the three pyramids doesn’t require turning either the sky or the world upside down (as the Orion idea requires), and Cygnus is a near-perfect match with the pyramids. Collins has also shown that key stars of Cygnus were actually visible above the three large pyramids when viewed from the southeast from the sacred mound of Gebel Ghibli. If the Cygnus alignment had been proposed before the Orion idea, the Cygnus alignment at Giza would have been the accepted one.

I’m sold.

Furthermore, there is a theory that the little pyramids indicate Orion, and its relative change in position from ancient times to the near future:

…where the three stars of Orion’s Belt were starting in 10,550 BC, known as The First Time. This alignment is to the southwest. The precession wheel cycle ends in AD 2400 when Orion’s Belt will be in the East, mimicked by the three small pyramids off the Great Pyramid.