The new NIH Public Access Policy became effective April 7, 2008 and calls for mandatory deposit in PubMed Central of peer-reviewed electronic manuscripts stemming from NIH funding. There are a number of resources available to help librarians respond to questions from researchers. One of the challenges is understanding the policies for specific publications. I hope these resources help.
Office of Extramural Research’s Public Access Policy Web site
Journals That Submit All NIH-Funded Final Published Articles to PubMed Central
Publisher policies on NIH-funded Authors (Open Access Directory Wiki)
Publishers’ Policies on the NIH Public Access Policy (From the Edward G. Miner Library, University of Rochester Medical Center)