Mendeley is a free product. You can register for and download the software here.
Like the other citation management software programs, Mendeley allows you to gather, organize and format your citations as you type. It also bills itself as an "academic social network" in that it makes it very easy to collaborate and share citations with other users as well as find researchers working on similar topics. You can attach PDFs to your citations in this system and there is a free ipad/iphone app available. Add the Web Importer to your browser to easily import content.
Mendeley also allows you to import your EndNote files into Mendeley if you should move to an institution that does not subscribe to EndNote web.
For more information and step-by-step instructions for attaching documents and other features, see the University of Akron's Reference Management Tools research guide.
Mendeley does offer a Blue Book Law Review style for its citations. It pulls its citation formats from Zotero so the citations will look substantially similar to those generated by Zotero.
1. Download Mendeley desktop version
2. Log in and click on the "View" link at the top of the page
3. Select "Citation Style" from the drop down menu
4. Click on "More Styles" and then click on the "Get more styles" tab
5. Search for "blue," select the Bluebook Law Review style and click "Install" (note there are multiple options--the middle option is the most recent)
6. Click "Done" to close
NOTE: No citation management service provides perfect Bluebook citations but they do give you a starting point. To see how well Mendeley stacks up against its competitors and the actual Bluebook itself in terms of citing to law review articles, books and cases see this comparison chart.