I read Howard Weatherly's reply. I agree with his thoughts with reservation as to style. I'd rather have an example than to talk about style. Also, style can be modified to the policies and procedures of the individual shop. I believe that some of the questions should include questions about the files (PRTF, DSPF, PF, LF, and Joined LF). These questions should include questions about the Copy DDS function and Subfiles. Another area that is becoming more popular is embedded SQL statements. Debug questions (both STRDBG and STRISDB) will help to identify good canidates. Questions that help you to identify if the person knows the AS/400 (and not just Cobol) would be very benificial. Questions about Job Scheduler, Sub-Systems (interactive vs. batch), how to indentify problems, how they would identify and solve the problems are good methods as well. A good programmer will know the system and how to utilize to it's strength.
If you need specific questions, let me know what areas you need to concentrate on.