If I use a wireless network to connect to the Internet does my ISP need a wireless network too?

If you use a wireless network to connect to the Internet, the wireless part only concerns your LAN. The communications link from your LAN to your Internet service provider (ISP) would be identical whether or not you had a wireless network. For example, if you connected an ethernet network to the Internet via a 56K modem, when you upgraded your network to use wireless, you would still use the same 56K modem to connect to the Internet.