I just signed up for Office 365, mainly for email at this point.
I went through the online steps and verified my domain, then I provided the FQDN for my website as I want that to stay at my current host. All that went pretty well. I then setup my domain in Office 365, csg-dfw.com.
This was about 5 hours ago. Now when I send myself an email from yahoo to my csg-dfw.com address, the email still comes to my old provider and not the Office 365.
I am sure I missed something as it seemed too easy that Microsoft made all the changes and I didn't have to do anything other than verify the domain and get the FQDN of my website.
Thanks for your help.