If you want to evaluate the system, use DETware tool from NIST.
A matlab script is available at http://www.itl.nist.gov/iad/mig//tools/
R package for the same is available here: http://sites.google.com/site/sretools/
> 2. I'm interested about identity of speaker presented in training set
> for test cross speaker identification ability. Where I can find this
> info?
The key file (sre04_key.txt) in the database has map for the target
speaker's id.
It means different things for different evaluation plans.
The map itself is available in a different file (model_speaker_map).
Make sure you use the latest key (http://www.itl.nist.gov/iad/mig/
tests/spk/2006/sre04_key.tgz)
Srikanth