I had no idea this even existed, but it was posted on the RPGSite Forums. I'm definitely interested, even though I've had a long love/hate relationship with the world.
Guide To Glorantha
On one hand, it has a fantastic mythology. On the other, I'm guessing 90% of the material is all about the Dragon Pass and Sartar region. I would jump on a book about the West, but it seems that Greg Stafford isn't all that interested in the area. I kind of think he only included it to make the general gaming public happy.
In any case, the books look great and I'm strongly considering jumping back into this world, even though I know I'll never actually game in it.