Struts 1.1? Any reason you are not using the latest version of Struts, 1.3.10? My personal advice is to use Struts 2, as it addresses several shortcomings in the Struts 1.x series (for example, Struts 2 does not have action forms!).
As for action forms, if your JSP's have the same data, it would make sense to use the same action form for each. If they have different data, you can either make different action forms for each JSP or use
DynaActionForm.