The charts can be configured to be updated at preset intervals with the new data.
The idea is to periodically update chart.dataProvider (or chart.dataSet[x].dataProvider in case of Stock chart) with the new datapoints, then just call chart.validateData() for the chart to take in the new data.
Here's a working example: http://jsfiddle.net/amcharts/ATQUm/
The data updates can be loaded using some AJAX techniques, like jQuery's getJSON method.
And here's an example of real-time Stock chart: