Because I couldn't find this ANYWHERE on the Google searches (maybe my own fault), I decided to publish my findings on how to get the Excel column letter from a number (aka: 2 => "B")

I'll presume that if you found this, you know how to reference a sheet, so I'll just throw in a one-liner that you should probably replace:
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This will take your number (column_number) and return a string (column_ref) in the form "$A:$A", with which you grab the letter however you want. The trimming of the string will vary from language to language, so I won't bother submitting that part. The real point of this thread was to hopefully get a thread on the Google results that shows everyone that it is possible to get the column letter from a number without some crazy function (and there are plenty of results with that). But those functions are language specific...

Unfortunately, I was confined to a semi-LabView language which has extremely limited capability. However, if you can get a .NET assembly reference to your Office Excel Library ##.0, then you can dump this into your code and be one step closer.