Announced shortly before the officialRoyal site was the Daily Mail's 'royaltyuk.com' site. This site provides some information free of charge, but requires a subscription for access to the majority of information. The subscription prices are given in US dollars, which betrays the site's target market; much of the information provided will be well-known to people in this country.
There are several other sites online which deal with specific items of information about the Royal Family -- the UK Guide site provides a nice potted history of Buckingham Palace, for instance.
Finally, for up-to-date news about the Royal Family, Geraldine Calcutt-Voost maintains a list of current information online. This site appears to be updated most days and brings together Royal-related news stories from around the Net.
Official Royal Family site:
Daily Mail site:
UK Guide Buckingham Palace page: