In a nutshell -- as I understand it -- the bill wants to prevent federally funded scientists from publishing their research findings anyplace but in expensive scientific journals that the layman has little or no access to, thus effectively preventing the public from knowing anything abut the research their tax dollars are paying for.
Here's the bill.
Read more about it:
I have to leave for work so I don't have time at the moment to research this myself. I'll get back to it later.