I know frames based pages are not search engine friendly, but what about iframes?

Most of my interface design is built around iframes to eliminate the annoying full screen redraw when the user just needs a small part of a page refreshed. That means the top page contains primary navigation, and a secondary page containing the main site content loads into an iframe.

Go to www.cruisetravel.com.au to see an example. The banner and the menu on the left are on the top page, while the stories and pics are in the content iframe.

When the search engine bot scans the page, does it see the iframe?
If so, how does it treat the iframe page? Does it scan the metatags of the iframe content?