When you go to Google and perform a search, it will return either one of two type of results:
Here is an example of option #2: http://37assets.s3.amazonaws.com/svn/grub-ellis-googlelisting.png
My website on a google.com search only lists my web page title (option #1), how do I get google to list my subpages on the search results (option #2)?
Is is an HTML issue? How do I get Google to know what my subpages are so that it can also list those on a google search.
Those are called "sitelinks" and are automated but you can partially configure them in Google's webmaster's tools. In webmaster's tools, click "sitelinks" in the navigation menu on the left. From the sitelinks page:
Sitelinks are links to a site's interior pages. Not all sites have sitelinks. Google generates these links automatically, but you can remove sitelinks you don't want.
Here is another Google page explaining sitelinks.