At the annual Worldwide Developer Conference in San Francisco, Apple announced that Snow Leopard (Mac OS X 10.6) will be available in September for $29 (if you're upgrading from Mac OS X Leopard), with Family Packs for up to 5 computers costing just $49 - again, if you're upgrading from 10.5. If you're running Mac OS X 10.4 Tiger on an Intel machine, the options are between a Mac Box Set (featuring Snow Leopard, iLife '09 and iWork '09) for $169 or 5-User Family Pack which brings you the iLife, iWork and Snow Leopard package for $229.

More info: Snow Leopard