The climbing permits go on sale tomorrow, Monday, February 1, at 9 AM through the Mount St. Helens Institute website.
Here's what the site says about permits:
Mount St. Helens offers an exciting and challenging climb. While it is not a technical climb and does not usually require special equipment or previous mountain climbing experience, it is a strenuous experience. Be prepared for snow, ice and changing weather conditions.
Permits are required year round. From November 1 through March 31, you can obtain permits at no charge from the Lone Fir Resort in Cougar, WA. From April 1 through October 31, you need to purchase a permit in advance from this site. From April 1 through May 15, there is no limit on the number of permits available. After May 15, permits are limited to 100 per day.