One of my favorite sites for creating citations is Easybib. http://www.easybib.com/

It is super easy to use and it is a free site. It allows the user to keep track of all citations as they are working on a project and then it puts the citations into proper format, MLA or APA ,so that the user can put it into a document. It is easy enough for elementary students to use.

You can also go to http://www.easybib.com/librarians for downloadable documents including Guidelines and structures for citing common sources in MLA & APA style.
Julie Pelletier