Yep, I've noticed quite a few unsecured wireless networks in my area. I don't use them for anything important, because there is a chance someone is watching, but it was nice when I first moved in and was waiting on cable internet to get installed.
It's the best when I goto friends apartments, there are a ton of open networks. It's fun to print stuff on random printers.
I recently upgraded to a pre-n wireless router, I think I gave my whole block a wireless network, but it's secured though.