I am a bit new to vb.net. I Want to make a custom shaped button in vb.net 2008 professional Edition. I Want to make it by Design and not by Code. Can Anyone Help me Please?

You cannot do it in the designer; You do it in code.

As ddanbe told you can not do with disigner.
You can do one more Thing that is:

Add PictureBox (Properties: Transparent)
Now add image to that Properties. (mousehover)
Now add another image. (mouseleave)
add third image (mouse click)
2.) Add the Codes as you add for the button.

I know This is not your point of view but this will atleast give you Irregular shape button look.