There is some news on this problem. There is a paper here: http://arxiv.org/pdf/1402.2184v1.pdf

It finds an example of size 1160 that has value 2 and proves that that example is maximal. The polymath 5 project found an example of size 1124. The proof that 1160 is maximal required a large computer proof. For more information see this post: http://gowers.wordpress.com/2014/02/11/recent-news-concerning-the-erdos-discrepancy-problem/