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I use http://www.xml-sitemaps.com/ as well its well worth the money. you want an accurate site map and you can always edit the text file if you are handy in xml.

Hi there, In order to tell Google that your sites are targeted to different locations (.com for the US and .co.uk for the UK) and that despite having very similar, almost duplicated content this is not the case you should: Add the rel="alternate" hreflang="x" tags to your pages, targeting them to their specific countries:  hreflang="en-gb" for the UK and hreflang="en-us" for the US. Like this you're specifying that these pages are both in English but targeting to different countries. Even if you're offering the exact same products or services try to differentiate the content by localizing key elements of your pages content. You can do this by adding the name of the countries (or cities if you have different content per cities) in your titles, meta descriptions, headings. Also adding the specific addresses and currencies you have for different countries too. Like this search engines will see that the content is not exactly the same and includes references to different locations. Take a look at this post I wrote some time ago where I shared the main criteria and aspects to take into consideration for International websites. Thanks!