The University of Virginia's government documents department has developed a web site that provides access to agency documents (including decisions) available on the Internet. This includes agency guidance documents, interpretation letters, as well as links to agencies' e-FOIA reading rooms.
Organized by agency and subject, this site provides a wealth of information in a cost-effective manner. The subject search is particularly helpful when you are
not aware of which agency might possibly regulate in the area you're researching. Although you may run across a broken link or two, the site still gives you enough context to locate that same information on your own (through backtracking the URL).
A disclaimer from the site:
This page is not an attempt to link to the Federal Register or the Code of Federal Regulations information for each federal agency. It links to other administrative actions which are outside the scope of the CFR or the FR. What is available via the Internet varies from agency to agency.
Last year when I asked my students to locate administrative decisions on an assignment, I thought I was clever by picking decisions that I thought could only be found on Westlaw and/or LexisNexis. To my delight, every single student chose the Virginia site to answer the questions and found every decision for which I was looking. Very nice indeed (and cost-effective)!