When using an iPad, connecting at a Starbucks, you will see a page pop up (like a web browser, but with no address bar), and it will allow you to login.
Apple has a KB article on them at: http://support.apple.com/kb/HT3867
However, I can't find any information on what configuration is required to emulate this. (i.e. a DHCP option, DNS setting, etc...)
Does anybody know how to make this happen on my wifi network?