Peercoin was created by Scott Nadal and Sunny King (who also developed Primecoin). Scott has since departed the project leaving Sunny King as the core maintainer.
Mining and Minting
Mining in Peercoin is much the same as bitcoin and used the same SHA256 hashing method, however block time, transaction fees and difficultly are all quite different (as described below).
Minting is based on Coin Age that is, the number of the coins multiplied by the number of days that they have been held. Coins must be held for 30 days before they are elidgilbe to begin minting and reach their maximum rate of minting at 90 days. The network target is a 1% yearly return on any coins allocated for minting. After a coin has successful minted it is frozen for 520 blocks. Thus users must make sure to remove coins from the minting process if they are preparing for a transaction.
As with mining, minting involves hashing. However, this is done on a per node basis and is done in a limited search space (one hash per unspent wallet output per second). This is done with the goal of reducing overall energy consumption of the network.
Peercoin retargets difficulty after each block. Difficulty is tracked separately for both the mining and minting process with minting being inversely difficult to mining. That is to say the network is designed to incentivize minting over mining, so as mining gets more difficult minting gets proportionally less difficult.
Peercoin transaction fees are fixed at the protocol level which is currently 0.01 PPC/kB.