A: You may want to look at the following reference:
Kistler, R., W. Collins, S. Saha, G. White, J. Woollen, E. Kalnay, M. Chelliah, W. Ebisuzaki, M. Kanamitsu, V. Kousky, H. van den Dool, R. Jenne, and M. Fiorino, 2001: The NCEP-NCAR 50-year reanalysis: monthly means CD-ROM and documentation. Bulletin of the American Meteorological Society, 82, 247-268.
It can be found online here. The following sites may also provide useful information for you.
http://wesley.wwb.noaa.gov/bams96.html
http://wesley.wwb.noaa.gov/reanalysis.html