Noob help for charting on web site, need assistance

I am new to the mailing list and to PostgreSQL.

I am currently running PostgreSQL 9.0.4 on a Windows XP laptop.

I am successfully logging sensor data to a database (temperature, humidity, voltage, etc…), I would like to display the
datain a chart on a web site. Currently I am have everything on the same Windows system, PostgreSQL, data acquisition
system,Apache Web server, pgAdmin III, and pgAgent. 

I am updating the database with a csv file (generated by the data acquisition system) with the COPY command in an SQL
script(updates every minute via SQL script and pgAgent). Not the best way, but it works for now. 

I would like to use something simple (if there is such a thing) to show a chart of sensor output over time base on a
SQLquery, e.g. hourly average past 24 hrs, daily average, weekly average, etc… The system is on a local network that
shouldnot be accessible from the outside network, behind a firewall with net10 address. Because some use Macs and
iPads,I can't use a Flash based product, eliminating some options.  

I have looked a number of charting "products", mostly based off of a google search and this page:
http://webtecker.com/2008/06/12/10-free-chart-scripts/

The charting "products" include the following:

Flot, Open Flash Chart, AmCharts, Emprise JavaScript Charts, PlotKit, Flotr, PHP/SWF Charts, Visifire, FusionCharts,
andJFreeChart.  

I appreciate any help in pointing me toward a solution and/or recommendations for how to graphically display sensor
dataover time. 

Regards,
Greg Howard