In addition to Einar's response, you can also add a property to frmB.

Public Class frmB

    Dim testValue As String

    Public Property Test()
        Get
            Return testValue
        End Get
        Set(ByVal value)
            testValue = value
        End Set
    End Property

End Class

And you could call your form like so:

Dim frmB1 AS New frmB
frmB1.Test = "Value I want to pass in"
frmB1.Show