I suggest creating a PictureBox and learning how to use the System.Drawing objects to draw the line on to the picturebox. It's pretty easy to get the hang of, below are a couple links:
Microsoft - Draw a line in a PictureBox VB and C# Great System.Drawing Tutorial - all in C# but once you understand the objects you can easily call the same subs/functions in VB
After reading that stuff, try it out and see what you can come up with. You can also google System.Drawing and start browsing through tutorials and source code from there.
There are also many (perhaps free) graphing and plotting controls available if you wanna go that way, I suggest typing something '.net graph control' or '.net chart control' in google and seeing what you come up with.
Happy Coding!
Adam