Answer

Mac OS X Lion bring on followin new features :

  • Multi touch gestures
  • Full screen applications
  • Mission Control
  • Auto Save and Versioning
  • Launch pad
  • Auto Resume of apps
  • Mac App Store — now with in-app purchase
  • Air Drop – P2P Wi-Fi networks
  • Newly designed Apple Mail
  • Better Search

It will only be available for download via the Mac App Store. The download size is about 4GB and will be upgrade will be priced at a very nominal price of $29.99.