from fedora to ubuntu

[Nat Gross]

Hi;
After many years on Fedora and Redhat, I am considering jumping ship.
My immediate concern of course is how quickly I can get up to speed with ubuntu.
Is there a document that details fundamental differences for folks
coming from fedora?
For example, can I use yum out of the box? More importantly is the
location of key files and directories off /etc, etc. [pun intended].

Thanks
nat