There are some huge IDEs like Eclipse with pydev, or Netbeans for Python. They however are very sluggish and force you to create a project for even the smallest test file. Eric isn't quite as sluggish.
I like the fast and nimble IDEs like PyScripter (Windows only), DrPython (only for Python2 right now), SPE (Python2 only at this point), Editra (does not handle console input well, but allows you to test drive different versions of Python quickly), and even the traditional IDLE.
For Each ctrl As Control In Me.Controls("pnlMainPanel").Controls
If ctrl.GetType Is GetType(System.Windows.Forms.Panel) Then
For Each subCtrl As Control In ctrl.Controls
If subCtrl.GetType Is GetType(System.Windows.Forms.TextBox) Then
If subCtrl.GetType Is ...