Question: $_* etc or $HTTP_*_VARS etc

I am going through some code that I wrote recently and trying to change it so that I can turn register globals off in my php.ini. However, before I do that I want to make sure I am using the right variables. I read in the manual that $HTTP_*_VARS has been 'replaced' by $_* is this correct? Should I be using $_* syntax then? The only reason I am asking instead of trusting the manual is because I'd hate to have misread something and thought I understood it, recoded my site, and then realized I used the wrong variables. So if someone could just tell me one or the other I'd be happy. (Oh I'm using php 4.1.1 if that makes a difference since I believe the manual said the $_* syntax started at 4.1.0?) Thanks, Zara