iCharts is a wonderful site for creating online interactive charts. This is done by either creating a chart from scratch or uploading one via Excel, Google Spreadsheet, etc. Once the chart is uploading a user can then customize their chart into how they want it look and then either post it online or embed into a site/blog.
Below is a demo on how to create a chart...
I highly recommend checking out iCharts by clicking here!!!
For similar sites check out ChartGo or Rich Chart Live.