It's called Main Street and the ad wasn't too informative beyond that. A search on the Scholastic site (which is horribly set up, IMO) reveals a chat transcript where she talks about it a bit.
Can you tell us anything about Main Street? It's about four friends whose grandmothers are in a knitting circle, right?
Well, that was close! It's about four young girls who are best friends. They live in the small town of Camden Falls, in New England, and the grandmothers of three of the girls own a sewing store on Main Street in town. The stories, which are contemporary, center around the girls, small-town happenings, and other people - including adults - in the town. The first book will be out in May of 2007, and the next three books will come out between then and May of 2008. After that, there will be two to three books a year.
When will the Main Street series begin?
The first book in the series will be called Welcome to Camden Falls and will be in stores May 2007.
Summary of the first book from Amazon: Welcome To Camden Falls - Flora and Ruby do not want to move to Camden Falls. But they don't really have a choice -- their parents are dead and their grandmother, Min, is taking them in. It's strange to be in a new place. But luckily, it's a very welcoming place. Min runs a sewing store, Needle & Thread, at the heart of Main Street in Camden Falls. There, Flora and Ruby become friends with Olivia, who likes to organize things, and Nikki, who lives on the wrong side of the tracks. Even if Flora and Ruby never expected it to, Camden Falls becomes their home . . . and its stories become a part of their stories.
I'm not really feeling any interest, especially after finding out more about it, but I thought some of you might like to know.