I teach lichen ID workshops and lead field walks periodically in the SF Bay Area and beyond–you can find details of upcoming events on twitter.
Lichen resources and groups
Checklist of North American lichens – The authoritative species list for the continent, updated periodically.
Ways of Enlichenment – Read Trevor Goward’s fascinating essay series. You’ll never see lichens the same way again.
California Lichen Society – California’s finest (and only) lichen organization. Join the listserv too to stay in the know about exciting lichen events.
Bulletin of the California Lichen Society – All the news on lichenology in California and beyond. Lots of interesting articles, field trip reports, etc.
Northwest Lichenologists – Arguably the energetic centroid of the North American lichen scene!