There's a few stories in the news lately about the Government of Southern Sudan disputing the 2007 and 2008 Sudanese national census effort.
Not to understate the argument, but the crux of the concerns involve a general under counting of the population of Southern Sudan. Any under counting would have longer term implications for resource distribution and representation in government and the Government of Southern Sudan (and frankly all of the regions and groups "not aligned with the center") are wise to voice their concerns and challenge the results. If the results of the census are based on sound research and sampling, then they are dependable. If not, then they need to be remedied quickly. Either way, it is an issue worth observing.
The Government of Southern Sudan has established an autonomous commission that compiles population data on Southern Sudan. The data includes livelihood profiles, and at-a-glance regional reports.