Subscriber Gateways aka Captive Portals:

http://www.station-server.com/
http://www.alvarion.com/Runtime/Products_2010.asp?tNodeParam=20
http://www.redmira.com 
http://www.intrago.co.uk/products/censornet.php?sc=0
http://www.cc.saga-u.ac.jp/opengate/index-e.html
http://www.demarctech.com/products/reliawave-ipnpsg.html
http://www.mtunow.com/2000technicaloverview.ppt
http://www.mikrotik.com  (w/ Hotspot Module)
http://www.nomadix.com
http://www.atreus-systems.com
http://www.viatornetworks.com
http://www.nocat.net
http://www.globaloop.com
http://www.bluesocket.com
http://www.solutioninc.com/
http://www.colubris.com/en/products/public_access/
http://www.airpath.com
http://www.lanroamer.net
http://www.geekspeed.net/wicap/
http://www.wifidelity.com/products.htm
http://www.sonicwall.com
http://www.logisense.com (TrafficXpress with their Cafe Module)
http://www.sputnik.com
http://www.ip3networks.com/
http://www.nnu.com
http://gambitwireless.com/wispspot.html
http://www.handlink.com.tw/eng/products/broadband/iss2000/products_broadband_iss2000.htm
http://www.pctel.com/