Actually, I'm gonna go with Andy on crappy how-to's dealing with skills.
I had the same experience with how-to drawing books. I bought, like, five, and ultimately the only thing I really learned was to stop buying them and just draw a lot.
Reading a lot would improve your writing, and photoreading would help you read a lot, so yeah, I can see it working now.
I guess the reason I was negative on this question before is that on the infomercial, I distinctly remember this one letter where a high school girl photoread a bunch of books one night then wrote a paper that gave her teacher an orgasm because it was so different from her normal work. Then it was like, she absorbed all the writing skill from those books she read and it changed the way she wrote.
I just don't like that "overnight" impression. Reading a lot over time will help, but not overnight.
But I agree with Andy in that you'll be reading a lot and this would help your writing.
Writing a lot will improve your writing. Definately agree.
-Ramon http://razor.ramon.com