I am trying to optimise a site for Google but it has a gateway page. It is an alcoholic beverage site so it requires an age verification page (the gateway). How can I allow Google to spider this site through the gateway page?
You could use cloaking. Basically, if the user-agent is google bot, then place a link on the page to your internal pages.
Alternativley, find a site which you know Google is indexing (perhaps you have a personal site?). Place a link from there to one of the internal pages in the site. Google will then follow the link. The higher the PR on the site with the link, the quicker Google will index it.