There are many discipline-specific as well as multi-disciplinary open access journals, with some links to collections appearing below. Choose journals for publication carefully; see "Vetting OA Journals" in this guide for more information, or contact your Research Librarian for help.
Need to get access to a full-text article and it's not available at W&M? Try a recently introduced extension for use with Chrome or Firefox, called Unpaywall. Once installed, this extension will help you to identify free, open access (OA) versions. Typically, these come from institutional repositories, such as W&M Publish. (Another reason for students and faculty to post their work there!)
Depositing your work in an open access repository is another way to share your research. Some of these sources are pre-print servers, where you can post article drafts for discussion with your peers. One recent study indicates that articles posted in biology pre-print servers are more highly cited than others. Be careful to comply with copyright and licensing restrictions when uploading your published work to one of these repositories.
Every publisher has different policies in regards to self-archiving and your subsequent use of your published work. The SHERPA/RoMEO database provides a searchable collection of publisher policies--check here when deciding where to publish.