The road to Mount Greylock is closed and scheduled to reopen in 2009. You can get updates on the official site which notes:
The road system is closed to all public access: automobiles, bicycles, and foot traffic for the 2007 and 2008 seasons. Roads are currently under repair for safety and access improvements. This affects public access to certain facilities; as a result the summit is not accessible by automobile, Bascom Lodge and the Veterans War Memorial Tower are closed, the campground (primitive overnight area) and Stony Ledge are accessible by hiking only. Full operation and access to these facilities are scheduled to resume in 2009 upon completion of the Historic Parkway road repairs. The Visitors Center and trails remain open.