http://www.ibmmainframes.com/
资源很丰富，包括了
Free Mainframe Software Downloads, Online Discussion Forum, Reference Manuals, Sample Programs, Mainframe JCLs, Mainframe Products, Interview QA, Information Zone, Mainframe Album etc..
Online Technical Support for VS COBOL II, IBM COBOL, Enterprise COBOL, MVS JCL, CICS, DB2/UDB, TSO, ISPF, IMS DB/DC, IDMS, VSAM, DFSORT, PL/I, ASSEMBLER, FILEAID, ABENDAID, XPEDITER, MQSERIES, EASYTRIEVE, ENDEVOR, COOLGEN, COBTEST, DITTO, CLIST, REXX and UNISYS Mainframes.