Inclusion in Google’s search results is free and easy; you don’t even need to submit your site to Google. Google is a fully automated search engine that uses software known as “spiders” to crawl the web on a regular basis and find sites to add to our index. In fact, the vast majority of sites listed in our results aren’t manually submitted for inclusion, but found and added automatically when google spiders crawl the web.

To ask Google to crawl a URL on a site you don’t own, visit https://www.google.com/webmasters/tools/submit-url/. However, if you own the site, google recommends that you follow the process below.

If you’ve just added a URL to your site, or a page has significantly changed since the last time it was crawled, you can ask Google to crawl it. (Google doesn’t guarantee that it will index every URL they crawl, however.)

Ask Google to crawl a page or site Steps:

  1. On the Webmaster Tools Home page, click the site you want.
  2. On the Dashboard, under Health, click Fetch as Google.
  3. In the text box, type the path to the page you want to check.
  4. In the dropdown list, select Web. (You can select another type of page, but currently we only accept submissions for our Web Search index.)
  5. Click Fetch. Google will fetch the URL you requested. It may take up to 10 or 15 minutes for Fetch status to be updated.
  6. Once you see a Fetch status of “Successful”, click Submit to Index, and then click one of the following:
    • To submit the individual URL to Google’s index, select URL and click Submit. You can submit up to 500 URLs a week in this way.
    • To submit the URL and all pages linked from it, click URL and all linked pages. You can submit up to 10 of these requests a month.

Source: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=1352276&topic=2371374&ctx=topic