If 11g, check out the following guides:
Enterprise Deployment Guide: http://docs.oracle.com/cd/E23943_01/core.1111/e12036/toc.htm for an best-practices approach to implementing an Enterprise Deployment
AIA Foundation Pack Installation Guide: http://docs.oracle.com/cd/E23943_01/doc.1111/e17949/toc.htm
At the AIA Foundation Pack Overview on Oracle Technology Network (http://www.oracle.com/technetwork/middleware/foundation-pack/overview/index.html) you can find the SOA-FP Cluster UPK which will give you a guided overview of performing a basic two-node cluster installation.
Once you have a complete SOA/FP installation on your cluster, then you can work on installing the Agile PIP.