EasyBib allows you to search books, websites, newspapers, journals, and databases in order to quickly generate a citation, which you can then copy and paste into a document, email to yourself, download as a Microsoft Word document, save to Google Docs, or save online for later use. EasyBib is intiutive and simple to use and since it's web-based, you don't have to worry about downloading any software to your computer. You can use EasyBib from any computer that has Internet access.
Generating citations using MLA is currently free but to create APA and Chicago/Turabian citations, you'll need to subscribe to MyBib Pro.