I've made a search on the Places API forum and I've found that in april, 2012 there wasn't any search option using radius. Now, almost one year latter, I'd like to know if you have any news about this.

I'm doing my searches using search?at={lat}%2C{lng}&q={business}&app_id={app_id}&app_code={app_code}&accept=application%2Fjson, but I need to limit the radius.