Once rumored as Ice Cream, Ice Cream Sandwich will follow OS 3.0, or Honeycomb, which landed on its first device, the Motorola Xoom, last week at CES. Availablity is uncertain, but one theory suggests that Ice Cream Sandwich would arrive as OS 2.4 later this summer.
The timeline makes sense, but the version number leaves me scratching my head. As to why Google would backtrack on the number isn't clear at this point. If anything, it would leave a lot of people confused and add fuel to the fire of fragmentation. Android 3.0 clearly is optimized for tablets, but it should make its way onto smartphones as well. Google has done a terrific job of letting developers see how the mobile OS has evolved, providing a platform versions chart among other tools.
I foresee Google officially announcing Android 3.0 when the Moto Xoom is ready to roll, which should be over the next two months. Ice Cream Sandwich then could make its debut in the summer, or perhaps in May at Google I/O. Regardless of when it does show up, Google certainly shows no sign of slowing release cycles down to around one per year.