This is not a request for help (how 'bout that?).

I'm sure this post will seem pretty darned lame to many experienced Zenners but I thought I'd post it for those Zen Carts noobs like me who use(d) Authorize.net (AIM) initially and were pulling their hair out. My version of Zen Cart is 1.3.8a, hosted on a GoDaddy shared Linux server (which BTW I have had absolutely NO problems with).

1. The Authorize.net (SIM) didn't work well at all. Why? My customer places an order and I receive a notice of payment from my merchant account, yet have no idea what the customer ordered. Going to the Admin Customer --> Orders looks like a ghost town as it pertains to CC customers, heck it shows they have an account and never ordered...ummm...not so buckwheat! Sheepishly I write to my customers (two, who happen to be dear friends...whew!) asking what they ordered. I then read here that SIM is not the ideal way to process through the Authorize.net gateway.

Lesson learned:
Scrap Authorize.net (SIM) -- DONE
Consider SSL certificate for site -- DONE

2. Obtained SSL certificate from GoDaddy. From start to finish (time from order until I could enter https:// in my browser and see my site) it took maybe one hour max (they are my domain registrar too). Very cool.

3. Setup Authorize.net (AIM). Erring to the side of caution I created a new Transaction ID and new MD5 Hash. Voila...setup complete.

4. Read how to modify configure.php (includes/configure.php). I was a tad baffled since my site appeared to be configured correctly, yet I was unable to checkout securely. Did my best Homer Simpson "DOH!" when I discovered this little line in configure.php:

// Use secure webserver for checkout procedure?
define('ENABLE_SSL', 'false');

Changed it to:
// Use secure webserver for checkout procedure?
define('ENABLE_SSL', 'true');

5. Take a deep breath and run a transaction.

Much to my pleasant surprise it went PERFECTLY.

Again, the only reason I'm posting this is to possibly help another newbie who might run into a similar issue. This process was incredibly simple in spite of my trepidation in getting my own SSL. I encourage others with similar reservations to consider this option.