So, what's the point of keeping a phone directory if you can't save your data? Add a text box for a file name, along with a Save button and a Load button to your 7.3 lab. Keep track of whether or not the current list has been changed from the last saved version, and warn the user if he or she is about to quit without saving.
While you're at it, change the organization of the data structure from parallel arrays to a single array of Structures.
HINTS: Have your program load and save the entire data set, rather than trying to change parts of the file. Make sure you format your file output in such a way that you can read the data back properly when you load the file. To run code when the Form is about to close, use the Me.FormClosing event.
As always, design a useful and proper interface.