**Fitch** should be available right here: *[Sovereign Ratings History][1]*

With **Moody's** it's not so easy, I don't know if there's a complete source available free of charge. But *[Sovereign Default and Recovery Rates, 1983-2007][2]* has some data in the appendix III, though not so up to date and in a not that convenient format.

Same goes about **S&P**, *[Sovereign Ratings History Since 1975][3]*.

Maybe someone will be able to come up with more edible formats though.


  [1]: http://www.fitchratings.com/web_content/ratings/sovereign_ratings_history.xls
  [2]: http://v2.moodys.com/cust/content/content.ashx?source=StaticContent/Free%20Pages/Credit%20Policy%20Research/documents/current/2007100000482445.pdf
  [3]: http://www2.standardandpoors.com/spf/pdf/fixedincome/KR_sovereign_SovRatingsHistorySince1975.pdf