From April 1st through October 31st, climbing permits for Mt St Helens are restricted to 100 per day, and demand for choice summer weekends is high. Unlike the Enchantments Permitting process, permits are first-come, first-served. So mark your calendars; here's the latest from the Mt St Helens Institute:

Permits from April 1 through October 31, 2013 will be available for purchase at $22.00 per permit on February 3, 2014 at 9:00 am on the Mount St. Helens Institute website's climbing page.

In my experience, nearly all the summer (late July - early Sept) weekends sell out within a few hours.