Litecoin is a peer-to-peer Internet currency that enables instant payments.
Litecoin (LTC) is one of the first "altcoins," or spinoffs of Bitcoin, and it's very similar to Bitcoin overall. Some of the major differences are that Litecoin processes network blocks in 2.5 minutes, a quarter of BItcoin's 10 minute time, and Litecoin is more complicated to mine than Bitcoin.