CVSSP collaborates with a few other organisations to maintain RAVL; an open source C++ computer vision library. It is available to download here.
In addition to data available on individual researchers' websites, CVSSP release a number of datasets to the research community. These include the biometric XM2VTS dataset and various object recognition datasets.
The website featurespace.org maintained by Dr Mikolajczk also collects a number of external object recognition datasets.