Yes, that is the plan. I'd expect to see them available soon after Core 2 Merom(laptop CPU) is released in August.
Also, there is speculation that some laptop developers will produce a Core 2 Conroe(desktop CPU) version for laptops aimed at those who want to replace their desktop PC with a laptop and aren't as worried about battery life. Don't know if this will be an offering by Mac though...if I ventured a guess, I'd say no.
Somtime in August/September timeframe for Core 2 Merom in Macs though to answer your question.