Dynamically Find SQL Instance Name for VBScript

Hello,
We have a Master Server environment and would like to push out an ActiveX job that gathers data about mountpoints on the server. We have all the code to gather the information but we are running into problems when we try to dynamically find the SQL instance name.  Our environment is cluster heavy with a myriad of 2+ node, 2+ instances, Active/Active, Active/Passive, etc.  Since the vbscript fires inside of a SQL Job I thought this would be easier.  So for example, I would have a generic piece of code on the Master server that pushes the job to the target servers.  When run, the job determines which SQL instance it is running on, gathers the required information and logs it to a table.  All the pieces are done except the "which server am I on" piece.  Any help would be appreciated.  Thanks.