With all the recent media attention, it seems like it is best to wait a bit before trying to download any of the data. The Japanese site (ERSDAC) published a warning earlier today that downloads may timeout, and I had a challenging time even getting the USGS site to load:
I have mentioned this before, but here is a paper on hydrology/glacier mapping in the Tien Shan mountain range using both ASTER and SRTM elevation data. One of the benefits of ASTER and other satellite sensors is that they are very applicable to remote area mapping operations.
So while you're waiting for ASTER traffic to subside, why not check out the ASTER User Handbook? It contains a wealth of background information on the sensor, data products, processing, applications, and FAQs. Here it is: