Google is rolling out an OTA upgrade to Ice Cream Sandwich for the Nexus S. GSM versions can already be updated manually. An early review is largely positive and comments on the significant visual and performance improvements. The Nexus S upgrade allows for a direct comparison against Gingerbread on the same hardware, and the likely improvement in current phones that will receive the upgrade.

http://mobile.slashdot.org/story/11/...-40-ics-update