I’ve just uploaded a spreadsheet of country codes (plain HTML view) to Google documents and spreadsheets. The spreadsheet includes ISO 3166-1 alpha-2, alpha-3, and numeric codes together with FIPS 10-4 codes, and the country names as provided in each spec. I originally created it to help me map FIPS to ISO codes from some air navigation data.
I’m interested in online data collaboration — what tools people need, how it will work in practice, etc. — and this seems like an easy way to experiment. If you’d like to make any corrections to the spreadsheet, let me know, and I’ll add you as a collaborator. I might also upload some spreadsheets of general geodata in the future, where there’s more opportunity for contributions.