Now Google in changed the algorithm based on their local search engine So you have to register the domain or modify the page information according to the local google. Software my Gaming Blog
Plesae Do not reply on old messages...the post is very old and all thinghs are changed.....its not useful to any one.
Bear in mind that if your site is hosted in the US it will impair the search position in the .co.uk results. Worth bearing in mind.
different database... for each language & each keywords, the calculate items are not the same for certain keywords... So the results are often not the same... but you watch one website, maybe you can find it on top 10, and maybe top 20 in another... Google.com & google.cn when input the chinese keywords, they returns the same. but when input the english keywords, most of them are different...
its depends on Google Data centers, and your doamin name TLD if your domain have .uk or.co.uk then it will show at Google.co.uk higher than others
Geo-location is a major ranking factor in all of the major search engines. This is why the results are different when you use a country-specific incarnation of Google, Yahoo!, MSN, etc. even if you do not request a country-specific search. The guiding principle here is the assumption that sites that are physically closer to the user will contain more relevant results. The major search engines use two common criteria in determining the geo-location of a site: (1) the presence of a Country Code Top Level Domain name (such as .co.uk, .com.au, etc.), and (2) for generic Top Level Domains (like .com, .net. .org, .info) they rely on the physical location of the server that hosts the site based on its IP address. Google will *sometimes* rely on the domain registration data, but no other factors are considered - not links, <meta> tags, page content, nor ritual incantations. Google will allow you to select a Geographic Target in the Webmaster Tools console if you have a generic TLD (although this obviously has no effect on the other search engines). You can even select a different Geographic Target on subdomains and subdirectories. But overall, this has been the state of things since at least 2002.
You should have 2 different website. For US it should be .com while for UK it should be .co.uk. IT will help you rank fast. Make sure to submit to each local directories.