Aaron,
Big question. Essentially, it is the same as you would do from VBA. Create
an in stance of Excel, and then navigate through the Excel object model
Dim xlApp As Object
Dim xlWorkbook As Object
Dim xlSheet As Object
Set xlApp = CreateObject("Excel.Application")
xlApp.Visible = True
Set xlWorkbook = xlApp.Workbooks.Open("C:\myTest\myFile.xls")
Set xlSheet = xlWorkbook.Worksheets(1)
MsgBox xlSheet.Range("A1")
xlApp.Quit
Set xlApp = Nothing