IPCC AR4 models all listed with lots of information and links (although some now dead): http://www-pcmdi.llnl.gov/ipcc/model_documentation/ipcc_mode...

For example, the three models developed by NASA: http://data.giss.nasa.gov/modelE/ar4/

Direct links to each model + code + datasets:

http://www.giss.nasa.gov/tools/modelE/ - with nightly code snapshots here: http://simplex.giss.nasa.gov/snapshots/

http://aom.giss.nasa.gov/ - with direct access to code here: http://aom.giss.nasa.gov/code.html and here: http://aom.giss.nasa.gov/code4x3.html

http://www.giss.nasa.gov/tools/modelii/ - seemingly work on this has now been merged with the ModelE simulation.

Lots of other code and data is available if you take the time to find it ... and then considerably more time to understand it.