Guide to Inspection of Computerized Systems in Drug Processing. This is from 1983 but is still worth reading as an historical document.
Glossary of Computerized System and Software Development Terminology.
Information on Electronic Signature regulations which came out last year.
General Principals of Software Validation - Draft Guidance. Medical Device Software Validation. Specifically addresses medical devices, but written based upon good software development practices and therefore applicable to other computer software.
FDA/ORA Regulatory Procedures Manual, August 1997. Chapter 4 explains the process for issuing warning letters.
Title 21 Code of Federal Regulations (21 CFR xx).