SCOTUS blog on US V ALA on the Supreme Court decision upholding CIPA enforcement of library filters. They also provide a brief accessible summary of the positions of the various justices.
Jenny Levine's got a collection of links on the case. You can tell she's not overly enamoured with the decision,
"This decision only points out even further how out of touch
our politicians and judges are with the daily lives of the
people they are supposed to represent. Obviously none of
them use the public libraries they just deemed themselves
knowledgeable enough to censor.

Final thought for the night: someone please correct me if
I'm wrong, but there's no additional funding for libraries to
start purchasing site licenses for filtering software, using staff
time and resources to create internal solutions, or
outsourcing the job of building something. So now we're
supposed to divert existing monies (that help pay for the
access itself?) from our already weakened budgets in order
to be compliant with this decision? I'm still looking for the
common sense logic here...."
I suspect one of the Chief Justice's arguments, which he will be most criticised for, by opponents of the decision will be: "A library’s failure to make quality-based judgments about all the materials it furnishes from the Web does not somehow taint the judgments it does make. A library’s need to exercise judgment in making collection decisions depends on its traditional role in identifying suitable and worthwhile material; it is no less entitled to play that roll when it collects material from the internet than when it collects material from any other source. Most libraries already exclude pornography from their print collections because they deem it inappropriate for inclusion. We do not subject these decisions to heightened scrutiny; it would make little sense to treat libraries’ judgments to block online pornography any differently, when they judgments are made for just the same reason.” He's not actually treating like with like here and is pre-supposing that the libraries define what gets filtered out. Whereas it is the software filter companies who decide what criteria are used for filtering. Justice Souter, who disagreed with the majority (6-3) opinion, argues that excluding porn from an existing set of resources is different from actively spending money on porn to include in those resources. For a self described luddite, that's a pretty good demonstration that he understands the difference between the 'push' nature of most conventional media versus the 'pull' nature of the Net. Chief Justice Rehnquist, in the paragraph quoted, doesn't display a direct awareness of the push v pull distinction. It's unfair to take the paragraph out of context and I have not yet read the entire 56 page ruling but that one jumped out at me a bit.
One of the concurring justices (can't remember which at the moment) seems to be primarily swayed by the argument that there is no big deal here. If library patrons want unfiltered access to the Net via a library computer, they can just ask the librarian to switch the filter off. The possibilty of such an outlet then brings the question of anonymity into play. I might find it no big deal to ask a librarian to switch a filter off because, for example, it happens to block access to a site like the Ethical Spectacle, maintained by a prominent critic of software filters, Jonathan Wallace. (The websites of people like Jonathan and Seth Finkelsteinhave been blacklisted by some filter software companies.) Others might not be prepared to ask a librarian to switch off a filter for fear of being perceived in a negative light as someone interested in pornography. In his dissent, Justice Souter, on this point said "First, the statute says only that a library 'may' unblock, not that it must...In addition, it allows unblocking only for a 'bona fide research or other lawful purposes'. There is therefore necessarily some restriction, which is surely made more onerous by the uncertainty of its terms and the generosity of its discretion to library staffs in deciding who gets complete Internet access and who does not." Absolutely.