I just finished updating the How To Guides for the three types of generated services (RFC, BOR, and Screen Scraping). The updated guides cover SP3 and SP4 functionality. It is important to note that new generator functionality will be coming out in SP5 and will be integrated in the Gateway Service Builder transaction - SEGW (first introduced in SP4). That said, the old generators will still be available and is what these updated how to guides cover.
Here are the links the guides:
RFC Generator - http://scn.sap.com/docs/DOC-5010
BOR Generator - http://scn.sap.com/docs/DOC-5009
Screen Scraping Generator - http://scn.sap.com/docs/DOC-5008
Let me know if you run into any issues or have any questions.