Some free services and domain registrars actually register the domain names in their names and let you use it for free.  This could prohibit you from transferring the domain to another host or registrar, or greatly complicate the issue.  A quick way to determine this is to check the WHOIS lookup on your domain names. You want to see YOUR name in the "registrant" field.  There are other records there for administrative and technical contacts.  These are alternate contact information for various administrative aspects of your domain.  Your name might appear here as well, or the information of your provider.  Again, it's the Registrant information that is the key for domain ownership. 

If anyone is unfamiliar with this little check, WHOIS is a domain lookup service (free) that draws information from the public record and reports the on the owner (registrant), who the top level registrar is, and other contact info.

You can Google for a test site, or or use the official Internic Whois search at http://www.internic.net/whois.html .  Also, our partner, Postshadow.com also provides a Whois search link at the bottom of the page in the footer.