I have had some extensive dealings with Load balancing and so I will do my best at answering your questions:
My load balancing structure was different, I had 2 Webservers that were Loadbalanced without this one server that you are talking about. Just 2 servers with a common IP address which can be done through the NLB setup wizard on Windows Server 2003+. Not sure what would happen in your case if the network load balanced server was to die, would the traffic get to any one of the two webservers? Not too sure about your set-up.
1. We are currently only in Dev and have not take Sitefinity live for any website yet, this will be our first.
2. We are going live next week.
3. We already have a Load Balanced envoirnment as described above, our servers are Windows 2003 with IIS 6.0
Here are the system requirements: http://www.sitefinity.com/documentation/installation-and-administration-guide/installing-sitefinity/system-requirements.aspx
It looks like your set-up will be fine, but I used Windows Server 2008 with IIS7+
4. Given that we have a working Load Balanced Envoirnment, what do we have to do next?
I had a complete copy of everything on both Webservers. I had nothing shared between the servers, because as soon as you share anything you create a single point of failure. So when you set-up your NLB you give the IP address and a domain name for it. After that you navigate to the domain name address and it takes you to either one of the webservers. So that will answer many of your below questions.
5. According to this statement in the link referred above
" Install Sitefinity to the central location from which each front end server in the cluster will access Sitefinity.
This must be a network share available to all servers"
a. Should we install Sitefinity on the Load Balanced Server (central server) or on both the web servers?
b. What is the machine key that is being referred to in the (2) point of the link?
The machine key is a randomly generated key that looks like this:
<machineKey validationKey="AEFF53E12A22F21880C6273B547E1CD35B439A74A5ED4744DCD1AD1ADCA3763DC7ADBEE58231C1BCB03838279A53F6493074D3E1113A42CABE9623D234E5B6E1" decryptionKey="2F0D0F495D769327AD12AAC7EF226FDFF4CF5081AC3199399C3F9F59A33DFC71" validation="SHA1" decryption="AES" />
And you can get them online from lets say: http://aspnetresources.com/tools/machineKey
It goes in the web.config in teh following position <machineKey ...></system.web> and also make sure that the identical key is on both sides.
c. We were planning on having a copy of the website (folder structure) on each of the webserver, shouldn't that be the case as there is a reference to a common shared location?
As i said.
d. Is there anyway to test the Load Balancing set up without actually hooking up the domain to the site but just have the code there and the IIS instances set up?
Yes, create your own environment. I must say, we have tested the NLB functionality quite a bit and now it is very robust.
6. The most important question I guess would be worst case we were not able to configure our site for using Load Balancing, what would be the consequeuences?
Not sure what you are referring to here. If you configure it properly then it will work, but make sure you test it properly once up and running with unplugging one side and then the other. Is your database dual redundant?
Also make sure you configure the two webservers in the system section. Its a must.
<add value="http://web-a.mydomain.com/" />
<add value="http://web-b.mydomain.com/" />
Hope it helps,