Lots of questions popping up lately about how to rank well on Google.co.uk vs. Google.com. Danny shared this nugget of gold at SEW today:
google uk is going to favor uk based sites by default, even if you don’t use the pages from the uk option. you want to do well in google.com, you should be using .com. want to do well in co.uk, use co.uk. want to do well in both? i’d use .com hosted out of the uk.
I’d add that links from UK hosted sites (whether .com or .co.uk) can help and worldwide links can help at .com. Any other suggestions?