Are We All Aliens? The New Case for Panspermia: Interviews with experts on panspermia and in other fields shows rising interest in the idea.
Cosmic Ancestry: The Modern Version of Panspermia: Transcript to an online chat with panspermia theorist Brig Klyce.
Cosmic Ancestry: The Modern Version of Panspermia: The Cosmic Ancestry hypothesis - about which this site has a large amount of information - treats all of evolution, not just the origin of life on Earth, as due to interaction with cosmic microorganisms.
Panspermia: Descriptive entry in The Encyclopedia of Astrobiology, Astronomy, and Spaceflight.
Panspermia Revisited: Short scientific article by John R. Gribbin. "Spreading of life-bearing spores across the Galaxy (panspermia) may be easier than is usually acknowledged."
Panspermia: Society for Life in Space (SOLIS) Society: Panspermia overview and technical papers.