This is just some advice / suggestions / checks that I would follow if
I was planning an on-the-fly from the beta to the official
And in no way should be considered a how-to . Unless it works
[If there was an official how-to that I was aware of I would post the link]
You should be careful as to what you actually install between now and the date of the final release of F8. If it was me, I'd probably hold off on installing anything at this point.
See the Release Schedule Release Schedule
You need to be aware of any 3rd party repos that you currently have installed as well. In theory, if the basic structure of their repo has not changed, then once you install the correct fedora-release package it should take care of the 3rd party repo configuration as well. [As the variables should get the release / arch etc. correct]
At the point of release there will be available a couple of key rpm packages for making the transition [correctly updating the repos / release etc.]. This of course will not be automatic. You will need to manually grab and install these.
You probably have something like fedora-release-7.9X currently installed.
To see what files are provided by fedora-release
rpm -q --filesbypkg fedora-release
Hopefully others can chime in and provide some tips / advice as well.
Rahul is likely to be the most knowledgeable in this area and able to provide much better guidance.