Many questions. Let's take a couple and see if we can't clear things up.
I understand that the equivalent services are in /etc/init where the services start/stop. But I assume that if I install a package it does not necessarily create a startup script in /etc/init right?
No when you install applications on Linux distros (ones that make use of package managers such as dpkg/APT, RPM/YUM, pacman, etc.), as part of the software being installed the package manager has a scripting "feature" similar to those found in Windows that can add scripts, create scripts, add users to the system, and start services after they're installed.
So how does one know what has been installed and is available in Linux (like we can in Windows from Start -> Programs)?
Easy. The same package managers that I mentioned above have commands you can use to query the system to find out what applications have been installed, what files are related to these packages etc. etc.
On Red Hat based distros you can use the command
rpm to find out information about the packages installed.
$ rpm -aq | head -5
To find out what files are part of a package:
$ rpm -ql pygame | head -5
How can it show me just the executable pieces to that are included in the package (the applications)? Most of the time executables are installed in certain locations on Linux,
/bin are 2 such directories. I usually search the RPM packages like so for these:
$ rpm -ql pygtk2 | grep "/bin"
$ rpm -ql httpd | grep -E "bin/|sbin/" | head -10