I am bringing into flash xml files via a web service connector and a data set
component. Bound to these are are various components to retreive differant
parts of data from the xml file. One of the strings that come into a text area
component is a URl which I want to use to populate the action for a button. The
action (url from xml string) would change depending on which data I have
selected in the populated datagrid component (array of xml ).

How are you selecting you data? Most simple action would be something like this.

myButton.onRelease = function() {
getURL(pathinyourXML, "_blank");

I'm stuck on the same issue.

I have been able to bind XML data to a comboBox, textArea, and a Loader but I
can't figure out how to bind an URL from an XML file to a button.

I tried your simple button action. How do I access the dynamic URL variable?
Is it possible to bind the data to the function?

Any help or additional ideas would be appreciated.