domain (not subdomain) routing

I have several websites that are all basically the same thing but with
a different layout and a different primary controller

- http://www.website1.com - has views/layouts/website1 and
controllers/website1
- http://www.website2.com - has views/layouts/website2 and
controllers/website2

Everything else is the same, DB, graphics, other views, etc...

So I though ...

- have 1 rails app
- have a virtual host in apache for each virtual app
- route requests for each domain to the same mongrel
- have rails route based on DOMAIN

Any idea how to do this. I'll check out the source to the
request_routing plugin.

Yes, you want the request routing plugin and the theme_support plugin.