You will need to get an account (http://grabz.it/register.aspx) at GrabzIt once you have this you need to add your authorized domain (http://grabz.it/account/domains.aspx) this stops people using your account resources.

Then get your application key place this where it says APPPLICATION KEY in the snipped below.

Change "http://www.google.com" to be the website of your choice.

Place this snippet anywhere within the body tag. Your screenshot should appear within a few seconds. You can have as many of these tags on the page as you like.

If you need to debug it they have a diagnostics panel (http://grabz.it/account/diagnostics/) there are also more options available.

    <script type="text/javascript"
    src="http://grabz.it/services/javascript.ashx?key=APPLICATION KEY&url=http://www.google.com">
    </script>