Well it seems our Apache built into OS X has mod ssl already compiled. Just enable it in the apache.conf file, read the mod ssl html manual and u should be able to get started with HTTPS on Darwin.
Works great for me.
Read the mod ssl manual to work out how to create a server key, and self sign to create a certificate for Apache.
(it is:
openssl genrsa -out server.key 1024
openssl req -new -x509 -days 365 -key server.key -out server.crt
)
You need to set the RANDFILE environment variable for a rand seed.
In the apache.conf I added another port (and also did one for 80, it seemed to take over otherwise), and then you must configure the Virtual Host section (at the bottom) to accept the 443 port. You can then do what u like there. I did an <IfModule mod_ssl.c> and within that I put all the necessary parameters (see the modssl manual), in particular one for the random seed as Darwin doesn't have one (/dev/random). In the VH turn on SSL (SSLEngine on) and it should work...
Tim