When, Apple announced the new features and availability of iLife '11. People figured that one unannounced "feature" would likely be that the iLife suite had been converted to 64 bit. After all, Snow Leopard has had more than enough time to mature out in the wild, and it seems that developers left and right have jumped onto the 64 bit bandwagon.
As Gear Live notes, this's sadly not the case. If you look at the screenshot of the Mac Activity Monitor above, you'll notice that the "64 bit" marker isn't present next to both iMovie '11 and iPhoto '11, and apparently same is with the Garageband '11. The iLife apps are still labeled as "Intel" rather than "Intel 64 bit.