Only Via knows... the expectation is that DDR motherboards will start to arrive in the next two months. DDR-SDRAM is already available from several sources (but it's not backwards compatible with PC1xx SDRAM).
Edit: it's worth mentioning that Fkloster is probably right. If we were right on the verge of getting them, the hardware reviewers would already have them. Usually the reviewers get the boards a month or so before they appear on the street (if not sooner). Since hardware sites who are reviewing/previewing DDR boards are using boards with Micron's Samurai chipset, it stands to reason that DDR boards based on other chipsets aren't like to arrive in the next 4-6 weeks.