How to use ui:include with parameters?

You need to nest <ui:param> inside <ui:include> to pass parameters to the included file.

<ui:include src="general.xhtml">
    <ui:param name="action" value="actionOne" />
</ui:include>

and in the include:

<h:commandButton action="#{action}" />

Note that this only supports strings, not action methods. For the latter you would need to upgrade to JSF 2.0 and use composite components.

In addition to BalusC's answer:

Note that this only supports strings, not action methods. For the latter you would need to upgrade to JSF 2.0 and use composite components.

There is a way to do this with JSF 1.2, though it's somewhat ugly:

<ui:include src="general.xhtml">
    <ui:param name="actionBean" value="#{myBackingBean}" />
    <ui:param name="actionMethod" value="edit" />
</ui:include>

and

<h:commandButton action="#{actionBean[actionMethod]}" />