I made this site a while ago to watch over Bitcoin prices for myself, and shared it maybe a month ago with HN.<p>Seeing as how prices lately have been tanking, here's a repost to hopefully help some people out while the prices are so volatile.<p>The service currently supports text/sms and e-mail alerts for most of the big exchanges (mtgox, bitstamp, coinbase, btce), and new users can get 20 free credits today.