There are numerous excellent internet resources on DNA.
For those wanting to participate in a DNA project, I recommend researching the following sites:
Family Tree DNA & My Heritage will accept the raw data from the other testing companies FREE. Ancestry & 23 and Me will not accept data from the other testing companies.
If you want to compare chromosomes across the various testing companies, you can download your raw data into GEDmatch FREE. It is only as good as the amount of people that include their data into this database.