Believe this when you see it. Sudan's government has made undertakings like this before, only to renege later. In this case there are multiple ways for it to renege.

In the department of "believe it when you see it," Warren Hoge in the NYT today: http://www.nytimes.com/2007/04/17/world/africa/17cnd-sudan.html?hp

Lately there has been a certain amount of happy talk in the media over supposed changes of direction by Khartoum, renewed Western diplomacy, Chinese interest in heading off Darfur-related bad publicity before the Beijing Olympics next year and so forth. Against this happy talk is a reality made manifest over the last four years, that the regime in Khartoum is sponsoring genocide because it wants to sponsor genocide. It isn't acting out of feelings of insecurity, or resentment of imperialism, or concern about access to natural resources. It is sponsoring the extermination of black non-Arab Africans because it believes in all sincerity that this population deserves to be exterminated. That is the point at which consideration of the Darfur problem has to start, or it will never lead anywhere.