Where To Get Apache

The obvious place to get the latest version of Apache is off of the Apache web site: http://www.apache.org. The source distribution file is apache_1.1.1.tar.gz while the Linux ELF binaries is apache_1.1-linux-ELF.tar.gz. Grab what you find is necessary...
If you are running Red Hat Linux 4.0 like I am, during the installation process you are allowed to select whether or not you want to install a web server. If you do, Red Hat 4.0 includes the latest Apache and installs everything automatically with a default configuration. This default configuration even RUNS correctly without any modifications! However, even in this case, please read my notes and preferences regarding installation in the next section.

Typically, unless you need to add special modules or features, the binary distribution or the default Red Hat installation should be fine. However, let's say you wanted to run Apache as a proxy server. In this case, you would need the source so you can compile the proxy module as part of the binary.
(Note: I have heard rumors that the binary included with Red Hat 4.0 has some bugs. I have yet to encounter any myself, so take that rumor with a big grain of salt.)