The State of Washington will, in the coming weeks, determine the new K-12 Math Standards. They have a draft set that folks can review.
The OSPI has promised to name three curricula which they regard as roughly aligned with the State Standards and they will support. Districts will not be required to adopt one of these three curricula (yet), but the OSPI has promised support for these three, which, if it materializes, would be a strong incentive for Districts to select one of them. The OSPI has promised that there will be at least one traditional math curricula among the three for each school level.
Seattle Public Schools has recently adopted math curricula for middle schools (CMP II) and elementary schools (Everyday Math supplemented by Singapore Math). This year, the District will adopt a new high school math curriculum. The District's math curriculum adoption web page is horribly out-of-date, but it offers the best information publicly available on the topic.
According to that web page, the District is considering these three curricula for high school math:
College Preparatory Mathematics [CPM]: Algebra Connections, Geometry Connections, Algebra 2
Key Press Interactive Mathematics Program [IMP]: Year 1, 2, 3, 4
McGraw-Hill-Glencoe Contemporary Mathematics in Context [Core-Plus]: Course 1, 2, 3, 4
I hear that some schools are already using IMP and some are already using Core-Plus.
The Board has scheduled a work session on High School Math Adoption for March 12. Curriculum adoption is a Board level decision, but I don't believe the Board would even consider overruling a recommendation from staff. The Board will select a curricula this Spring and that curricula will be implemented in the fall of 2008. As with the middle school and elementary school math adoption, we can expect that high schools will be required to implement the selected curricula unless they get a waiver.