With VIA finally being able to market their Pentium 4 chipsets, most larger manufacturers are expected to be jumping on the bandwagon, ASUS and MSI seem to be the first to have boards in the works according to Digitimes.
Unlike the videocard market, usually mobo makers have no problem distributing products based on competing chipsets from Intel, SiS, VIA, ALi, or any other.

It's going to be an interesting situation, let's remember VIA once developed a P4 chipset that performed better than those from Intel & SiS at the time, unfortunately they couldn't market the chip... SiS should be worried.

According to the companies’ schedules, MSI is expected to be the first manufacturer to release the PT400 board, which will be available in May. Asustek said that its PT400 motherboards will hit the market in June.