Google is having problems in indexing localized pages with .com TLDs within a country. The sites which are hosted in countries other than United States of America such as United Kingdom and Australia with com TLDs, are showing in Google.com but do not come up in Google.co.uk or Google.com.au. This problem has been persisting since August of 2006 according to a WebmasterWorld Forums thread and has once again cropped up on New Year eve. A search for a site on Google.com and on Google.co.uk and Google.com.au will show the site. But if you chose the option of 'pages from Australia' and 'pages from the UK' the index page of the site does not show.
More and more people who are facing this problem are posting their questions at Google Groups.