[vba] Get User Selected Range

How can I get a range of cells selected via user mouse input for further processing using VBA?

This depends on what you mean by "get the range of selection". If you mean getting the range address (like "A1:B1") then use the Address property of Selection object - as Michael stated Selection object is much like a Range object, so most properties and methods works on it.

Sub test()
    Dim myString As String
    myString = Selection.Address
End Sub

Selection is its own object within VBA. It functions much like a Range object.

Selection and Range do not share all the same properties and methods, though, so for ease of use it might make sense just to create a range and set it equal to the Selection, then you can deal with it programmatically like any other range.

Dim myRange as Range
Set myRange = Selection

For further reading, check out the MSDN article.