I reached out to the fling creator Ivan Donchev and he was kind enough to help assist me in the issues I ran into and also provided an updated version of his script to properly handle both the power state and the CSRF workaround. He recently published an update to his script a few weeks back supporting both ESX 4 and ESXi 5 but missed ESX(i) 4.1 support due to limited amount of testing. This was an easy fix and I modified the script to include support for ESX(i) 4.1 and also changed the default power off operation to a guestOS shutdown. The modified version of the script can be downloaded here.
When you browse to the homepage of your ESX(i) host using the browser, you will be prompted to login which require the same credentials as if you were to login to the host directly using the vSphere Client or vSphere MOB.
To load the Ops Panel script on an ESX(i) host, you will need to do the following:
Note: These instructions are applicable for both ESX and ESXi, but with ESXi, it is important that the commands to copy both the modified index.html and Ops Panel script to docroot are executed as changes are not persisted after a reboot for ESXi hosts.
You can also add this to your kickstart file by appending the lines above in your %firstboot stanza so you automatically get Ops Panel after install. Though this will not give you a full webAccess that classic ESX did but it definitely is a useful way to quickly get to your virtual machines and perform simple power operations using a web browser.