From the incredible minds at Google :)

http://code.google.com/apis/chart/

This impressive little library lets you generate PNG chart files from a single URL request string.  Since people typically need to pass lots and lots of data for charting, they came up with a really creative way to compress the values, and provide a javascript snippet for automating the process.

So the nifty chart you see to the right is a "hello world" app using their API.  It ultimately comes down to a simple URL request of:

http://chart.apis.google.com/chart?cht=p3&chd=s:hW&chs=250x100&chl=Hello|World

Quite impressive and easy to use!

While this doesn't provide the stellar interactivity and depth of integration that Flex charts do, it certainly provides a way to do nice looking charts with a quick turn-around. 

According to their docs, you can freely use this so long as you don't regularly exceed the 50,000 hits per day limit at which point they may block you.  I think most of us will not be hitting it quite this much.

Some samples: