If you know a little bit of scripting and you are in Linux, you can make a simple script (using curl or wget for instance) that do exactly what you want. Check this out.

I use Bitcoin Checker in my phone, it has a plethora of exchanges but it doesn't have Bitcoincharts, most probably because Bitcoincharts doesn't seem to be a Bitcoin exchange, thus being irrelevant for the use of a price alert app.

In this open source app you can track Bitcoin price in different exchanges and set the alert to a % of variation from the last price, I think it is a great app.

You can try this bitcoin price alert service. It isn't tied specifically to bitcoincharts, but it supports some of the bigger exchanges and can send notifications through text or e-mail.