There have been a series of hold-ups with Intel's new Ivy Bridge processor line, but according to CPU World the wait is almost over; some of the new mobile and desktop quad-core chips will be launched before the end of April.
The launch, however, seems to be just for the fastest of the chips. From CPU World:
"Ivy Bridge processors will be announced in the 4th week of April, between April 22 and April 28. The announcement will include only quad-core models: mobile Core i7 and Core i7 Extreme families, desktop Core i7, Core i5-3570K, i5-3570T, i5-3550, i5-3550S, i5-3450 and i5-3450S. The announced chips will be available for sale on April 29, and the reviews and benchmarks should be published on the same day. Specifications and prices of these processors are provided below:"
Those are all quad-core processors, with clock speeds ranging from 2.5 GHz to 3.5 GHz, which is great news for the desk-bound and those who use high-performance laptops.
For those wanting Ivy Bridge in their ultraportable—or perhaps even in the 2012 range of slimmed-down MacBook Pros—you can expect a longer wait. For those applications, expect to see one of the dual-core processors, which according to CPU World should launch at the start of June. [CPU World via Mac Rumors]