What is "open access?" check out this link to an 8 minute cartoon from PhD (Piled Higher and Deeper) Comics to see an explanatory video of open access. Learning can be fun!
Purdue Libraries support open access by providing a place where faculty and researchers can deposit their papers so other can read them. It's called ePubs.
Even if you published in non-open access journals, you may be able to submit your articles to ePUB. Many publishers allow authors to submit the last submitted version of their paper in a university repository.