Here is a simple code that will publish to IFTTT if the temperatur gets to hot, this code will get you started but maybe you should add some more functions that will notify you when the temperatur is in the correct range again and things like that.
Class Temperature
Shared Event GetTemp() RaiseEvent Every 1 Minutes
Dim Temp As Float = TempSensor.GetTemp
Dim tempstring As String = Temp.ToString()
If Temp > 5 Then
//Temperatur is more then 5
Lplan.IFTTT("Your key", "NameofRecipe", tempstring, "", "")
Else
//Temperatur is not more then 5
End If
End Event
End Class
When you add this code in mcStudio then you also need to add the TempSensor library from File/Add Library Code.
And now you need to create a IFTTT recipe
Trigger channel "Maker"
Action Channel "Gmail"
and select Send an Email, now you could receive an email when the temperatur gets to high.
Let me know if any part of this need better explanation or if you have other questions.