The International Building Code is the one harmonized model building code that has been developed for use in the entire country. It has already had two distinct editions, in 2000 and 2003, and the process is underway to create the 2006 edition.
For those who are unfamiliar with the code change process of the International Code Council, the developer of the IBC, a brief summary is provided here. There are two main parts to the code development process. First are the code development hearings and approximately seven months later are the final action hearings.