Access to the SDN is unfortunately restricted to Beta users, but there is a public section with a Web Application Server Developer Edition Sneak Preview (600MB) for download. Also very interesting are the SAPInsider articles, which give a good insight into the upcoming technologies, as well as information on J2EE technologies in SAP WebAS on help.sap.com.
The related information contains some very nice screenshots of SAP's new Eclipse-based tools. Looks like the developers at SAP have been very busy. (I do hope they intend on giving back some of their efforts to the Eclipse project!) Furthermore, some of the screenshots remind of what I have seen of Visual Studio.NET. Maybe someone out there is interested in writing up a comparison of the two company's technologies? Looks like SAP and Microsoft are competing (older article) more and more in similar arenas, vying for the same customers, in spite of close business relationships in the past.