Is this blend available right now? their website states april through june 2009.
You might be able to find some places that still have some in stock, but Wyeast has moved on to their next set of strains
The WYeast lambic blend is all the same stuff just in different proportions
In past communication with Brian Perkey, I've learned that the Roeselare will be a year-round offering, so it should be easy to find.
Of the sites/shops I normally use, Austin has it, I'm sure some others do too.