using yum to upgrade from rh8 to fedora core 2

[bruce]

hi

i have a few rh8 servers that i access remotely. i need to know what's the
best way to use yum to upgrade the systems to fedora (1 or 2). i've seen
bits of information/sites on the net that lead me to believe it can be done.
however, i'm not exactly sure what's the right procedure.

can someone give me pointers, or a site that i can get to that will provide
seriously basic steps as to the correct process.

i'm running
 httpd
 mysql
 gnome
 vncserver
 nfs
 etc...

and i don't want to screw up the current apps being run on the servers..

thanks

bruce