I have a QLineEdit, and I need to know if there is a signal which can track mouse hover over that QLineEdit, and once mouse is over that QLineEdit it emits a signal.
I have seen the documents, and found we have the following signals: 

cursorPositionChanged ( int old, int new )
  editingFinished ()
  returnPressed ()
  selectionChanged ()
  textChanged ( const QString & text )
  textEdited ( const QString & text )  

However, none of this is exactly for hover-over. Can you suggest if this can be done by any other way in PyQt4?
You can use enterEvent, leaveEvent, enterEvent is triggered when mouse enters the widget and leave event is triggered when the mouse leaves the widget. These events are in the QWidget class, QLineEdit inherits QWidget, so you can use these events in QLineEdit. I you don't see these events in QLineEdit's documentation, click on the link List of all members, including inherited members at the top of the page.
QLineEdit hover-over Signal - when mouse is over the QlineEdit