Ulf-Dietrich Reips has published extensively on the nature of online research methods. On this website, many of his publications can be accessed in an open-source format.
Scott Plous of Wesleyan University maintains a resource of online social psychology studies here. It’s a big resource with references to papers, links to how-to guides, software suggestions, and much more.
The team at psychology.org has put together this article that covers a lot of ground in terms of tips and skills for online research in psychology.