There are several ways to determine which journals may be relevant to your research. This can help you in browsing current updates, and also to determine where you may want to submit your research results for publication.
Many of our research databases have the ability to give you a ranked list of journals from a particular set of search results. These will tell you which publications feature articles on your topic most often. Here are some screen shots for different databases to help you see where to look:
EBSCOhost databases (Academic Search Complete, ERIC, APA Psycinfo, etc.):
To truly be part of the conversation, you need to know where those conversations are happening in your discipline.
For many academic fields, this means the published journal literature, but also at conferences and symposia, in pre-print archives (especially in physics and computer science), or in online discussions.
You may want to join social networking sites for academics and researchers... these are sites that allow you to discuss and join groups or make connections around your academic field of interest. Some examples are:
Another source for finding networks of researchers would be the scholarly society of your discipline or sub-discipline. Though a bit out of date, the Scholarly Societies Project would be a good place to start, or ask your research advisor/mentor.
Sometimes, it's not where you are, but who you know... There are often prominent scholars in a field that it would be good to familiarize yourself with their work. Alternatively, there may be another research group that is doing similar research to you and it would be a good idea to stay up to date with what they're doing (either competitively or cooperatively).
Just as you can get a ranked list of publications from a database, many will also let you produce a list of who has authored the most papers on a particular subject, or which universities are doing research on a topic from a specific set of search results.