Is it profitable to use Amazon EC2 to mine litecoins? I saw that mining BTC with CPU is not profitable anymore, and that you'd lose money mining bitcoin. Is the same thing true of litecoin?
Yes it can be worth it, but generally what happens is if it ever is worth it then a huge number of people start doing it until the prices of EC2 are driven up and it is no longer profitable. Here is a good blog post about the subject:

http://da-data.blogspot.com/2013/12/briefly-profitable-alt-coin-mining-on.html