Give this a try, you must have the field in your report first though...
Private Sub Form2_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
Dim Report1 As New CrystalReport1
Report1.SetParameterValue("crTextBox", Form1.TextBox1.Text)
CrystalReportViewer1.ReportSource = Report1
End Sub
In the SetParameterValue you specify the field name from your report and the field you want from your form or whatever it maybe; in your case your variable.