As you may already know, the Law Library maintains a username and password for PACER (Public Access to Court Electronic Records, http://pacer.psc.uscourts.gov/), which is available for use by current members of the Law School community. PACER provides online access to U.S. District, Bankruptcy, and Appellate court records and docket information, with many documents available in PDF.
The major disadvantage of PACER is its pay-per-view charging system, which costs searchers $0.08/page. This can add up quickly! One solution is to first review the free docket information available on Justia's Federal District Court Filings & Dockets page (http://dockets.justia.com/) to identify exactly which documents are desired before logging in to PACER. In addition, a good amount of PACER's content is available to Law School users on Westlaw; available document PDFs will be linked at the bottom of the associated case.
However, a recent initiative by public.resource.org offers another promising method for obtaining PACER documents. At http://pacer.resource.org/, researchers are invited to "Recycle Your Used PACER Documents!" by uploading them to resource.org's already large repository of law-related government documents (which are not subject to copyright restrictions). The available documents can be reviewed and downloaded by other users (for free) at http://bulk.resource.org/courts.gov/pacer/.
Be sure to bookmark the PACER document repository (http://bulk.resource.org/courts.gov/pacer/), and add it to your list of sources to check when researching federal dockets and court documents.