I was further behind the curve on this one than I thought. A reader enlightens me:
Hi John,
This actually has been going on in one form or another since the late 1980s in the US. By the mid-1990s lightweight GPS units made recovery even more reliable, before then we were limited to radio direction-finding techniques to locate where a package landed. With a GPS you could find out the landing site to within 50 feet.
There are dozens of groups around the US and a few overseas in countries with lighter aviation and radio regulations. A large sub-group of this community uses Amateur Radio to transmit the data — its main website is here. The participants range from professional scientists and educators to tinkerers of all sorts. Many flights are conducted with an educational component to them, from elementary school kids to university engineering students.
My own small contribution to this community can be found here (we have done 40-some flights) with a few videos here and pictures here.
This is truly wonderful. These tinkerers are keeping alive the great tradition of American technological creativity. All strength to them!