http://libguides.polk.edu/content.php?pid=54648&sid=693055
Here's a set of links on a community college website. They have examples of how to do the citations, and there's even some links at the bottom that you can use to have a computer generate your bibliography. Easybib makes a better bibliography, but the citation machine gives you a sample parenthetical citation. Word 2007 and up also have this stuff built in.
Edit: Whoops, I misread the first post. As was noted a few posts up, MLA is terrible at citing websites. The basic rule is, if you can get the author's name, just put that up and leave out the page number. If you can't, but it's still a reputable enough source to use in an MLA paper, just put up the URL. Databases are a special case, because they're usually electronic copies of physical journal articles, so you would cite those exactly like you would any other journal article.