Use the openSSL package that you can get at
http://www.openssl.org. 

After you have installed openSSL, execute the following commands:

openssl genrsa  -out server.key 
openssl req -new -x509 -days 730 -key server.key -out server.pem 

These commands will create two files server.key and server.pem. Put
them in this directory and configure your virtual host file to use these
files adding the following lines under the <VHOST> section:

<SSL_PRIVATEKEY>certificates/server.key</SSL_PRIVATEKEY>
<SSL_CERTIFICATE>certificates/server.pem</SSL_CERTIFICATE>
<SSL_PASSWORD></SSL_PASSWORD>