Assume you’re interested in Jones Day v. Blockshopper, pending in U.S. District Court for the Northern District of Illinois.
Go to Justia.com and click on the link US District Courts’ civil case filings. You can search for th
e docket of any federal district court case to find the case in Justia. Justia follows the Jones Day case here. If you click on that link and scroll down you’ll see the docket entries for the case (the last entry is #52 as of my writing of this post). You can click on the items to see filings and court orders.
Click on the “RSS” feed link on the top right of the Justia page for this case. 
Video Tutorial
Choose the RSS feed that you use. I use iGoogle.com, and once I click on the RSS feed I can select IGoogle. If you don’t have an RSS feed go to iGoogle.com and sign up. 
You are done – every time you check your iGoogle page you will see the titles of recent docket entries for this case, and you can click through to see the entry in more detail and access a filing or court order. You can follow as many cases as you like in this manner.