The date had been floating around the rumor mill for some time now, but Intel just officially announced that the next generation Core processors, codenamed Haswell, will be introduced on June 4 at the Computex event. From that moment on the new processor will go on sale along with their corresponding motherboards.
You can expect an extensive in-depth review from us that day. Considering the announcement will be made at Computex, it's safe to assume that the motherboard manufacturers will pull out all the stops to show off their Haswell-compatible products as well.
Whether or not Haswell-based laptops will be in stores already on 4 June, or whether it's only an announcement, Intel did not specify.