changing a slave to a master in mysql replication

[Vicky Gonzalez]

Currently to make a slave a master, the docs say you need to set the bin-log option in
my.cnf on the slave, and that will make the transition to master quicker. I know I can
manually change a slave to a master by stopping the slave process, stop mysql, take a
snapshot of the databases, copy over a new master my.cnf, make sure I have granted rights
to a user for the "old" master to return as a slave, and restart. 

My question is how does having the bin-log option on the slave actually help this process?
Or is there an easier way to convert a slave to master using the log position that I
missed?

Thanks in advance for any help.
~Vicky