You need to have mod-ssl installed. You also need OpenSSL which is used by
mod-ssl.
Install OpenSSL first. More info is available at:

www.openssl.org

You have to generate some keys!
- You should make a CA if you do not already have one. (using CA.sh
-newca)
- Then make a certificate request using openssl
- and then sign the certificate

Then install mod-ssl

If you are using Debian:

apt-get install apache  libapache-mod-ssl

will install apache1.3 and mod-ssl.
If you already have apache installed then try:

apt-get install libapache-mod-ssl

For more info visit:

www.modssl.org