SHA-256 alternate cryptocurrencies

Alt coins using SHA-256, the same hashing algorithm as Bitcoin.

    NMC – Namecoin
    PPC – PPCoin (Peercoin)
    DVC – Devcoin
    TRC – Terracoin
    BTE – Bytecoin
    IXC – Ixcoin
    I0C – I0coin
    FRC – Freicoin
    BLC – Blakecoin

Scrypt alternate cryptocurrencies

Alt coins using scrypt algorithm

    LTC – Litecoin
    NVC – Novacoin
    FTC – FeatherCoin
    MNC – MinCoin
    BBQ – BBQcoin
    TAG – Tagcoin
    MEG – Memorycoin
    BTCs/BTC2 – Bitcoin Scrypt

Alternate cryptocurrencies can be mined using the same hardware as for mining Bitcoins (mostly SHA-256 alt coins). While bitcoin mining is going to use FPGA and ASIC devices, scrypt based alt coins can be mined using GPU cards.
Other alternate cryptocurrencies

Alt coins using other, innovative hashing algorithms

    XPM – Primecoin
    QRK – Quark
    SRC – Securecoin
    Nxt – Next
    SKN – Skeincoin
    PTS – Protoshares
    Curecoin
    OFF – Offerings to Cthulhu
    HTC – Huitongbi
    PGC – Pangucoin