The G Bitch Spot wrote about the Ms Magazine petition. The idea is that in the 1972 inaugural issue of Ms, 53 well-known women in the US said that they'd had abortions (that is, before they were legal in most states), and that they supported women's rights to have access to abortions.
The new petition is asking people to say that they, too, have had abortions (if they have) and that they support choice. And those who haven't had abortions can sign in support.
I've never had an abortion, thanks to ready access to birth control (and the education to know how to use it), cooperative partners, and just plain luck. But if I'd gotten pregnant, I would have gotten an abortion if I could have. I signed in support. Especially, I signed in support of the many friends who've had abortions, and whom I love and for whom I'm glad they had access.
Go read the G Bitch Spot's post, because it's important.
Here's the petition on-line.