NATTING_help

[compuomari]

Dears,
I have a scenario that is somehow making me have a hardtime , i have a
wiless access point that get the internat access from my linux box, i
want any user that uses my internet to get a lnading page for my self (
some kind of advertisment ) and then go to the internet , i don't need
authentication , but i dont want this landing page occuring many more
than once for the user ... anyhow , how can i do it with iptables? i
want to DNAT all users to an internal apache server , then SNAT them to
the inernet , how is that possible? double natting? proxying ? i need
your help ..

regards,

oozie