Through googling, i found that we can create object in VB.net same way as VB6.
I deployed sample com in my local machine.
Then i called the com using the code
addobj = CreateObject("SimpleCalculator.AddNumbers")
And i called the function in button click event as
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
val1 = TextBox1.Text
val2 = TextBox2.Text
MsgBox(addobj.add(val1, val2))
End Sub
Now it works fine.