Have you installed the m2eclipse plugin? If so, you can create a Maven Project. Then the POM editor will let you search the repositories for the dependencies you are interested in. Some dependencies might not be in Maven Central, so you will have to locate the repository they belong to and ad that repository to your settings.xml file (or you can add it to your pom.xml, or you can installed a repository manager such as Nexus and have it manage all of that for you. Personally, I would go with Nexus, that removes a lot of headaches.)
For Hibernate, and other JBoss-related artifacts, see this:
http://community.jboss.org/wiki/MavenRepository