http://ethereum.stackexchange.com/questions/191/how-can-i-se...
For #3, an introduction is:
https://blog.ethereum.org/2015/12/24/understanding-serenity-...
and the improvement proposal is: https://github.com/ethereum/EIPs/issues/28
For #1, there are checksums now, but the more interesting question and challenge is how would a decentralized registry/DNS be designed, that has reasonable anti-incentives for squatters?
https://github.com/ethereum/EIPs/issues/26