In the Library: Nearly every database and our online catalog and SHU all have citation generators built in and most of these will customize the citation to just about any style you need (MLA, APA, etc.).
On the Web: There are also numerous sites that you are probably already well-aware of (like EasyBib) that do the work of making citations for you. We've gathered some that we think work well on our Citation Tools page.
Just be aware that the citations you copy are often slightly flawed and will need to be checked before adding to your final bibliography!