Keeping Google-friendly

Whenever I change or update any of my websites, I always go to Google's webmaster tools to keep everything up to date.
It's a site worth visiting anyway because if you use Google sitemaps, you really need to ensure that they are up to date. If they are not, Google reports an error and stops indexing the site. You then need to update the sitemap and re-submit it.
When you do that, it can take a while for Google to go and check the site out again, but you really mustn't forget to go and look at the results. If there are still errors, your site's changes won't be updated in Google's database.

Google likes sites with Google sitemaps, so it's worth investing the time to create one. However, creating one by hand is not a lot of fun and prone to error unless you really like writing XML.
There are plenty of tools out there for generating Google sitemaps.

Another advantage of using Google sitemaps is that submitting your sitemap to Google is a much faster way of getting your site indexed by Google than simply by submitting its URL.

You can visit Google's webmaster pages at http://www.google.com/webmasters.