You don't have to initialize mysql db : it will be done automagically when you'll start the mysqld service for the first time (service mysqld start) ... Have a look in the mysqld init script (that rpm/yum provides you so gently) , especially in the start() function ...
Well, I guess that's a DOH on my part. Of course they'd provide and use the init scripts in /etc/init.d.
This may have something to do with all the previous things I've attempted after the install, but when I actually invoke the script it says the startup fails. However, the mysql.log shows that the database successfully starts, and I'm able to get a mysql prompt.
Thanks for your help. === Al