Spin Street had the Criterion edition of The Third Man in stock the last time I was there, and The Sons picked it for tonight. I'm sorry I hadn't seen this film before. Graham Greene wrote the screenplay. Starring are Joseph Cotton, Trevor Howard and Orson Welles. The Third Man is 3rd on imdb's list of top films noir and was on the last AFI Top 100 list but was removed from this one due to its lack of sufficient American credentials.
It has been much discussed and reviewed:
filmsite (9/12/2007: link removed because I'm so tired of all the pop-ups at that site)
Bright Lights Film Journal
Like Television has the film online with commercials:
LikeTelevision Embed Movies and TV Shows
The Criterion Collection blog has a review.
1001 Flicks has a review.
Movie Zeal has a review as a part of their month of noir.
Noir of the Week reviews it here.