Joe,
I have a PS3, and I purchased the 20 dollar PS bluetooth remote. It is money well spent. Others have said using the game contoller is no big deal. For me, it was cumbersome. The dedicated remote is just as easy as any other DVD remote.
I have heard that you can get a USB dongle to get the Harmony to work. It wont work otherwise, as PS3 is bluetooth. I am still in the stone ages, and I don't have a Harmony. I love swapping between all of my remote controls! Well, not really...but anyway...
I will say that I am less than thrilled with upconversion on the PS3 for regular DVD. I prefer my Toshiba HD DVD for it, but the load times are painfully long. But BluRay....OM freaking G! Check out Ratatoui (SP?) or Casino Royale!
Scottiemon