The library has a collection of websites and style manuals that will help you in preparing a bibliography in MLA format. The full list of resources can be found here.
Many of the databases where you find articles have the ability to create a citation for you. This citation can then be cut and pasted into your bibliography. The screenshots below highlight where the citation tool is within various databases.
Proquest Education
Professional Development - EBSCO Education
There are several electronic tools that can help you create citations.