Cobol and OO-Cobol Compilers
Merant/Microfocus [Multiple OS, commercial]
LegacyJ PECobol [Multiple OS, commercial]
Tiny Cobol [Open source, GPL, Cobol 85]
Cobol to C compiler [Open source, GPL, Cobol 85]
Cobol for GCC [Open source, GPL, Cobol 85]
Grammars Home Page at the Free University of Amsterdam (they have free and browsable grammars for VS COBOL II and Standard Cobol )
Tutorials on object-oriented Cobol
Standards
Draft of ISO/IEC FCD 1989:2001 (contains object-oriented features) from the NCITS/J4 Standards Commitee for Cobol [plain PDF, 7MB] [zipped, 2.4 MB]
ANSI X3.23-1985 (R1991): Programming languages -- Cobol ($18 at ANSI)
ISO 1989:1985: Programming languages - Cobol (Endorsement of ANSI standard X3.23-1985) ($10 at ANSI)
Books
Advanced Cobol for Structured and Object-Oriented Programming
An Introduction to Object Cobol
Standard Object-Oriented Cobol