Hi John,
You might look into using creating a TagExtraInfo class that allows you to set a scripting variable from the ZipCode tag extension that's accessible to your page (and ultimately, your bean, I believe).
I like William's idea, too - I use that technique a lot with tag extensions, as it affords some flexibility in using and manipulating the tag extension's 'return value'. In fact, the Jakarta
Struts framework employs this approach for enabling communication between beans and tag extensions.
Hope that helps,
Chris