The biblatex-mla package seems to do a good job with basic MLA style citations and bibliographies. Here is an example of how to use it. You need to run latex biber latex latex to get everything to look right.
Update (July, 2016)
It seems that development of biblatex-mla has resumed. Using the latest version on CTAN this example compiles properly. I would strongly recommend you update your TeX distribution to TL 2016 instead of manually installing the package, since there have been many changes to both biblatex and biber which will also need to be updated, so manual updating will likely lead to package dependency conflicts.
Various previous problems with biblatex-mla may have been fixed with this new version, so the warning on the previous version of this answer may not apply.
Previous Warning
As the comments have mentioned, and also this question: biblatex-mla sometimes \autocite[prenote][pg]{key} is not printing the author's name there seem to be significant problems with biblatex-mla which hasn't been updated for some time. It may need to be used with biblatex version 1.0.
\documentclass[12pt,letterpaper]{article}
\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[style=mla,backend=biber]{biblatex}
\begin{filecontents}{mla-test-bib.bib}
@article{Kavanaugh1976,
Author = {Kavanaugh, Robert D.},
Journal = {Child Development},
Month = {Sep},
Number = {3},
Pages = {885-887},
Title = {On the Synonymity of `more' and `less': Comments on a Methodology},
Volume = {47},
Year = {1976}}
@book{Saussure1995,
Author = {Ferdinand de Saussure},
Publisher = {Payot},
Title = {Cours de Linguistique G{\'e}n{\'e}rale},
Year = {1995}}
\end{filecontents} % This is the end of the sample bibliography
\addbibresource{mla-test-bib.bib} % you would use your own bib file here
\begin{document}
This is a citation. \autocite{Saussure1995}. Another citation \autocite{Kavanaugh1976}
\printbibliography
\end{document}
If you need footnote citations, use the package option autocite=footnote and add the following code to your preamble (based on the solution posted here: Biblatex-mla gives me a \smartcite error).
\DeclareAutoCiteCommand{footnote}[f]{\footcite}{\footcites}
If you need to change the title of the bibliography to something other than "Works Cited", add the following code to your preamble:
\defbibheading{bibliography}{%
\section*{Bibliography}} %use \chapter* if the bibliography will be a chapter

biblatex. It isn't complete though and hasn't been updated for quite some time. I actually contacted its author some time and got no response. – Simifilm Feb 17 '12 at 20:20