Google Scholar is a great starting place for initial research. Unlike a regular Google search, Google Scholar attempts to connect you with more scholarly content then information typically found on the web.
Most of the time when searching for information on Google Scholar you will be connected with the article record from the publishers website. You can use the same evaluation criteria you use when reviewing an article from a library database to determine if articles from the web are peer-reviewed. See if you can easily identify the author, journal the article was published in, author credentials, etc.
Below are a few other things to keep in mind when evaluating information published on the web.
For more information on web information evaluation see the detailed sheet from the Meriam Library at the California State University, Chico.