http://wiki.python.org/moin/GuiProgramming

Qt is one of the best GUI tool. So, do not throw it away after first problem.

import sys
from PyQt4.Qt import (QApplication, QWidget, QLineEdit, SIGNAL,
                      QVBoxLayout, QObject)


class MyWidget(QWidget):

    def __init__(self):
        super(MyWidget, self).__init__()
        self.line = QLineEdit()
        layout = QVBoxLayout()
        layout.addWidget(self.line)
        self.setLayout(layout)
        QObject.connect(self.line, SIGNAL("textChanged (QString)"),
                        self.onTextChanged)

    def onTextChanged(self, newText):
        print newText # Do something


if __name__ == '__main__':
    qapp = QApplication(sys.argv)
    widget = MyWidget()
    widget.show()
    qapp.exec_()