While getting results for: site:mydomain.com I don't get results for: cache:mydomain.com Please note that the site is very new. So, can I take it that Google found it, but haven't chached it yet?
yes you are correct. if you sign up for google's sitemaps and submit a sitemap it gives you a lot more info about your site.
It's possible that mydomain.com/index.htm (for example) is indexed but mydomain.com is not. You can get this situation if you have links to both versions of the same site; Google thinks that one is a duplicate. If that is so, you should redirect one to the other.