set of training images for a simple neural network

do you know any good set of training images for my test neural network

preferably a tagged set of images of numb开发者_开发问答ers or letters or simple symbols

faces or real images might be too complex at this stage. (i am tiring to implement a Boltzmann machine)

The UCI Machine Learning Repository has a bunch of different sets of training data, including handwritten digits, for example Optical Recognition of Handwritten Digits Data Set

Another large repository of datasets, organized by application domain (classification, regression, segmentation, ...) is MLcomp. It also allow you to compare the performance of your algorithm with many other standard methods.