General Mainframe sites:
CA
IBM Mainframe
IBM Destination z
Education Library:
IBM z/OS Solutions Information Center
FTP Directory of IBM Presentations
IBM Certification Education Sites:
IBM Certified Database Associate - DB2 9 Fundamentals
IBM Certified Database
Administrator - DB2 9 DBA for z/OS
IBM Certified Application
Developer - DB2 9
Development Leading Edge:
DB2 purXML
Developer Works
Alpha Works
Web Developer Forum
User Groups:
DB2 International
User Group
Midwest
Database User Group (Chicago)
General DB2 sites:
DB2USA
DB2 Pod Cast
Interesting DB2 Sites