my site www.maldivescards.com was expired and it was blank for more than a month and i was looking to re-register it and it was registered by some other guys who buy expired domains by using back-order.
i search google and the domain is still in google however when i search dmoz.org its removed.
Pages can stay in Google for many months. We changed our entire site layout, and all page names for optimisation etc. but they were still in Google, and we were still gettin errors in the error log from people looking for the pages 4+ months later.
Just get rid of the pages, or better still replace them with 301 redirects to the new page. Make sure you're new pages are linked well so that Google picks them up real quick and replaces your old pages so you don't lose traffic