http://www.working-families.org/

Since its inception in 1992, the Labor Project is a national non-profit organization that focuses on building awareness and agreements among labor, advocacy and community groups to improve family-friendly workplace policies such as family leave, paid sick days and employee-controlled flexibility.
Labor unions protect the very class of employees that we've learned are the hardest hit by lack of workplace flexibility. Union jobs are the hands-on jobs that can't be done from a home office or on a flex schedule. The Labor Project was established to address work-life issues found throughout labor unions. The intended audience for its website includes union employees and union leaders looking to incorporate family-friendly programs in their contracts.
Netsy Firestein is the founder and executive director of the Labor Project. Many of the articles and whitepapers available on this site are written by her. Netsy is recognized as a national expert on labor and work family issues. She has guided several unions in developing bargaining language and strategy and negotiating for work-family programs. She was also instrumental in the passage of California's first paid family leave law. The Labor Project partners with many credible research teams, including teams from UC Berkeley, the Center for American Progress, the Institute for Women's Policy Research, and more.
The site is biased toward union employees and what's in it for them to incorporate family-friendly language into their contracts. It does, however, provide best practices (what works, what doesn't work) and explanation of how the community benefits when employers offer such benefits. I think the key piece missing from this website is the WIIFM for organizations…explanation of improved engagement, retention, etc. Overall, I think this is a valuable site for its intended audience; however, coming at the issue from all sides (specifically from company views) would lend even more credibility to its content.

Just thought I, too, would note the websites I'm working with:
http://www.worklifebalancecentre.org/ and http://www.lifebalanceinstitute.com/.