There is a welath of material by and about Phillip Johnson on the Web.
Additional Resources
Access Research Network's Phillip Johnson Page is perhaps the primary resource for all things related to Phillip Johnson.
Here you will find lecture videos, archives of Phil's Weekly Wedge Update and Leading Edge Columns from Touchstone Magazine as well as a speaking schedule and other resources.
Phil's publisher, Intervarsity Press, has a section on him as well.
Leadership University has many of Phil's articles online in his own Virtual Office.
Ross A. Taylor, in his "Creation and Revelation" pages has compiled another resource page for Phil.
Phil is also an advisor to Seattle's Discovery Institue, an organization commited to discovering "policies that will shape the future in the common-sense tradition of representative government, the free market, and individual liberty".
His page at DI is here