Under the "Storage Adapters" section of the vCenter management tool for the second ESX box I successfully added an iSCSI software adapter and connected it to the same LUN I used on the first ESX box. I am pretty sure I did this correctly since the "Dynamic Discovery" option for the storage adapter was able to find the IP address and even added the correct static IP addresses for the LUN.
The only problem I run into is when I try to "Add Storage" in the "Storage" section of the managing the second ESX box. It doesn't show any LUNs to choose from when I try to "Add Storage".