Snow Leopard calls it httpd and Ubuntu apache2. Are there any differences? One difference is apache2ctl on Ubuntu and apachectl on Snow Leopard.
Well, httpd is basically just the same as apache2 in most modern operating systems. Of course, you should check an actual version of Apache in your system because minor version numbers can (and will) differ.
On Snow Leopard, I see this:
On Lucid, I see this:
So, yes, essentially the same. The difference in naming probably has to do with historic packaging conventions at Ubuntu and Apple. RHEL, for what it's worth, also calls its Apache2 package "httpd".