VS 2008 Alternative To A 2 Dimensionable Array?

I'm writing an app that reads zip files from a folder and then displays them in a listbox. As a user clicks on one of the zip files in the list they can see a particular file that is located inside the zip archive in a textbox. The way I'm doing this now is to read the files from the folder and store the zip file name and the file associated with it into a two dimensional array. Kind of like this:

Dim a_files(500, 1) a_files(0,0) = name of zip file in folder a_files(0,1) = name of a particular file in the zip file The problem is that there may be more than 500 files so the array has to be scalable. I know you can use 'ReDim Preserve' to resize the right element on the fly, but I need to resize the left element. I've looked at collections, but I can't see an example where they can be multidimensional. Does someone know of an alternative way to store these values that would have the flexibility I need?