Reed Cartwright is correct about how the Lemon test ought to be applied--and of course he's right about the real intent of the authors of the law in question. What I find interesting about the law is its careful, even scrupulous avoidance of the teaching of religion.
The text of the act says:"Every...teacher...shall have the affirmative right and freedom to present scientific information pertaining to the full range of scientific views concerning biological or physical origins in any curricula or course of learning," (§ 3) and that "No...teacher...shall be terminated, disciplined...[et cetera] for promoting scientific information pertaining to the full range of scientific views concerning biological or physical origins." (§ 4). Of course, the First Amendment already protects a teacher's right to present scientific evidence--and even to discuss non-scientific views, like ID or creationism, so long as it is not done in a way that stamps these latter things with any government imprimatur. If the law were simply intended to protect the right of a teacher to present scientific evidence, then it's totally unnecessary, since freedom of speech already protects that right. And if it were intended to protect the right of a teacher to discuss religion as an academic discipline, it would again be unnecessary, since the First Amendment protects that, as well. The law goes on to provide that while "[s]tudents may be evaluated based on their understanding of course materials," they may not "be penalized in any way" for "subscrib[ing] to a particular position on biological or physical origins." (§ 5). Again, this is already the case, due to the First Amendment.
The law would therefore be redundant unless it's intended to encourage teachers to teach creationism. Yet the law then specifically disclaims this intention: "Nothing in this act shall be construed as...encouraging any change in the state curriculum standards," (§ 6) and "Nothing in this act shall be construed as promoting any religious doctrine...or promoting discirmination for or against religion or non-religion." (§ 7).
So there are two things that this law is intended to do. First, it is intended to placate religious conservatives who demand that the legislature "Do Something" to compromise evolution education, while at the same time not doing anything substantive. That's a possibility, and no doubt some legislators voted for it because they saw it would let them appear noble in the eyes of their constituents, while doing no real damage.
But second, and more sinister, is that the law will encourage teachers to go into class and teach ID creationism as if it were a "scientific view[ ]" protected by this law. Then, if a teacher is disciplined by a principal who wishes to preserve the quality of science education in his school, the teacher will file suit, arguing that ID is "science" and therefore protected by the law. So this law is designed to create a test case on the scientific validity of ID creationism.
Some might think this isn't such a big deal, because science will most likely win such a case, the way it did in McLean v. Arkansas Bd. of Ed., 529 F.Supp. 1255 (E.D.Ark. 1982). But the problem with that is that school principals are unlikely to want to bring on such a lawsuit. Lawsuits are a big hassle; they take a lot of time and involve many lawyers. So the most likely practical effect of this law is to provide a disincentive for principals to ensure the scientific integrity of evolution education in their schools, because they will be less likely to call teachers to task for teaching creationism in class--while the law simultaneously emboldens teachers to do so. Alabamans who care about the scientific education of their children ought to be outraged at their lawmakers for instituting what is at the very least a massive waste of time and resources.