[clug] apt naming convention

[Chris Smart]

I'm playing with Debian on a box of mine and I'm a little confused.
Installing various packages from the repository I generally just do
"apt-get install package" but sometimes it's not available and I find
variants. Sometimes it is there but there are other options, like
package-bin, package-common, even package-new or package-old, sometimes
has versions like package-2 or package2 and sometimes package as well as
package-common with the same description? Some are libpackage others are
package-lib.. etc

Some others make sense to me like postfix-mysql and postfix-ldap,
apf-client and apf-server, but in general the naming convention seems
strange to me. There is apache-common, apache2-common and apache2.2-common
and I'm confused.

I'm hoping someone can help me understand it better so I don't go crazy :)

Thanks!
Chris