ereg

Hoping someone can help me here. I'm working with someone else's code and I'm not familiar with ereg_replace(), can someone provide me an alternative to the following? ereg_replace("[^a-z0-9._]", "", ereg_replace (" ", "_", ereg_replace("%20", "_", strtolower($original_name)))); Basically, I want to enter $original_name and have it come out $new_name, converting all spaces to underscores, upper to lowercase, and whatever that first line does. :) I've read through the manual and what I got was that preg_replace() is probably faster... Anyhow, I looked up preg_replace() and as a newbie to PHP, the given examples look like a language all their own. Thanks, Jason