For multiple files: TABS2Spaces (http://bluefive.pair.com/tabs2spaces.htm http://bluefive.pair.com/tabs2spaces.htm), which is a GUI application, and tabspace (h

For multiple files: TABS2Spaces (http://bluefive.pair.com/tabs2spaces.htm http://bluefive.pair.com/tabs2spaces.htm), which is a GUI application, and tabspace (http://stefanstools.sourceforge.net/tabspace.html http://stefanstools.sourceforge.net/tabspace.html), which is a CLI one. The latter also removes trailing whitespace (though it can be told not to via the /leaveeol parameter).