A citation manager will make keeping track of your sources and formatting your citations much easier, and it's best to set one up before you start collecting them. You can also add notes to your sources, which can help you get started on your annotated bibliography.
I recommend Zotero because it seamlessly integrates with your browser, making it easy to grab information right off the web or from a database. Zotero also offers plugins for Google Docs and Microsoft Word that make it easy to add your citations as your write.
Need help getting set up? Visit my office or email me!