If you are using Lightroom on a 64 bit capable Mac you will be glad to know the latest update to Snow Leopard (10.6.2) fixes the bug that crippled the sending of multiple photos from Lightroom to Photoshop for editing. Previously, if you selected 3 or more photos in Lightroom and tried to send them to Photoshop for panorama stitching, HDR merging or opening as layers Photoshop would open but no photos would appear. The short term fix for this was to run Lightroom in 32 bit mode and all functionality for sending to Photoshop was restored. The downside being that you couldn’t run Lightroom in 64 bit mode.
So, install the 10.6.2 update from Apple, then right-click on the Lightroom icon in your Applications folder and uncheck the Open in 32 bit mode box, then launch Lightroom and give it a test drive. You should be back in business!