JQuery: Eliminar tildes y eñes

var normalize = (function() {
  var from = "ÃÀÁÄÂÈÉËÊÌÍÏÎÒÓÖÔÙÚÜÛãàáäâèéëêìíïîòóöôùúüûÑñÇç",
      to   = "AAAAAEEEEIIIIOOOOUUUUaaaaaeeeeiiiioooouuuunncc",
      mapping = {};

  for(var i = 0, j = from.length; i < j; i++ )
      mapping[ from.charAt( i ) ] = to.charAt( i );

  return function( str ) {
      var ret = [];
      for( var i = 0, j = str.length; i < j; i++ ) {
          var c = str.charAt( i );
          if( mapping.hasOwnProperty( str.charAt( i ) ) )
              ret.push( mapping[ c ] );
          else
              ret.push( c );
      }
      return ret.join( '' );
  }

})();

Más información en http://www.etnassoft.com/2011/03/03/eliminar-tildes-con-javascript/