Apple's yearly developer conference should see iOS 8, OS X 10.10, and likely some hardware.
Apple Seeds Rumored Golden Master Mac OS X 10.6 (10A432) to Developers
Snow Leopard represents the next major version of Mac OS X to be released to consumers and has been officially scheduled for September, though there has been some suggestion that it could appear later this month. Snow Leopard will provide a number of "under the hood" enhancements that should improve performance and stability.
Mac OS X Snow Leopard will be priced at $29 for current OS X Leopard owners, and users purchasing a new Mac on June 8th, 2009 or later can receive the updated operating system for $9.95 though Apple's "Up to Date" program.