If you have purcahsed a computer or Xserve from Apple on June 08, 2009 or later that does not include Snow Leopard, you can upgrade it for only $9.95. The deal is valid till December 26, 2009 and 90 days after the purchase. Your computer is qualified foe this deal if it was sold by Apple Authorized dealer between the two above mentioned dates and does not include MAC OS X v 10.6 (Snow Leopard). The qualifying Xserve includes MA882LL/A, MB449LL/A. Z0E7, Z0FR and Z0GM.
Snow Leopard contains upgrades that were necessary for ‘Mac OS X’ as well as some enhanced user experience and new features. If you have purchased many computers on a single invoice, you can purchase only 1 up gradation and request Right-to-Copy for others.
There may not be a lot of people who fit into this category, so if they are interested they need to buy it for higher price. The price is $29 if you are upgrading from Leopard, $49 for a Family-Pack. As apple says: this OS makes MAC an MAC, and yet snow leopard is claimed to be more refined so upgrading is vital for users. The new version promises a lot of refinements, the most important is faster start and shutdown time. The wake up time is 2x faster than previous version and shutdown is 1.8x faster. Moreover snow leopard requires half the space for installation than previous version thus frees 7 GB of your storage. View the complete list of major refinments.