As noted in a blog post over a month ago, there were many things added to the tax-free weekend. Instead of just shoes and clothes, now most school supplies priced under $100 are a part of the tax-free goodness.
The holiday runs from August 21-23, 2009. This is a bit later than usual but most public schools are starting later in the year than in the past, so the later date is a direct result of that. To see a full list of all tax-free items, visit the official State Comptroller's site.