Function LeapYear(ByVal YYYY As Long) As Boolean
LeapYear = YYYY Mod 4 = 0 _
And (YYYY Mod 100 <> 0 Or YYYY Mod 400 = 0)
End Function
Function LeapYear2(ByVal YYYY As Long) As Boolean
LeapYear2 = Month(DateSerial(YYYY, 2, 29)) = 2
End Function

Private Sub Form_Load()
MsgBox LeapYear(1971)
MsgBox LeapYear2(2000)
End Sub