As things stand, government departments, much like universities, must pay twice for research results - once, to fund the research, and again, to read the research results (or do without). Among other things, FRPAA will mean better access to the research literature for staffers at government agencies, at no cost for the research funded by the government agencies themselves - as it should be. For the taxpayer, this means better service (through a better-informed civil service), at less cost. This also eliminates the probability that the taxpayer is actually paying for the results of the research not just twice, as previously thought - but often thrice, or more (as explained below), without the taxpayer actually having access to the results at all! A situation that FRPAA will most definitely alleviate.
One of the ironies of scholarly publishing is that the producers of the research are also the customers. This is true not only in academia, but for the research funders, too.
How things work now is that a U.S. government department may provide the funding that makes research possible, but the results of the research are published in a scholarly journal - which is not available to the staff at the government department, unless they pay, either by subscription or on a per-article basis.
What this means is that, like universities and the taxpayer in general, government departments are often paying twice for the same research results - first, to conduct the research, and then, to pay to read the results. For the taxpayer, this means that access to research results is often paid for several times over, not just twice as we have been thinking. That is, the taxpayer pays to fund the research, then contributes to university subscriptions so that researchers can actually read the results of the research, then often pays again so that the staff at the government department which funded the research can read the results. The taxpayer may be paying more than thrice, of course, if the research results are needed by more than one government department. And - even after paying thrice, as things stand, the taxpayer still does not have rights to read the results of the research, unless the taxpayer pays yet again!
While the prime benefit of FRPAA will be enhanced access to research results for the researchers themselves, free access for the government staff means better tools for them to do their work, at less cost.
More information about the Federal Research Public Access Act of 2006 can be found at the Alliance for Taxpayer Access web site. See also Peter Suber's excellent overview in the May 2006 SPARC Open Access Newsletter, and keep up on developments by following Open Access News.