[raju]

When you say zoomable charts, do you mean like the one here http://www.highcharts.com/demo/dynamic-master-detail ?

flot.js has zooming/panning capabilities - http://people.iola.dk/olau/flot/examples/selection.html

This, assuming I understood what you were getting at.

Needless to say, HighCharts is slick - but flot.js has a nice price tag :)