FOR ATI
download cgminer: http://ck.kolivas.org/apps/cgminer/
tutorial (for LTC): http://cryptocur.com/litecoin/litecoin-ltc-gpu-mining/

FOR NVidia (if you want to use for mining)
cudaminer: https://bitcointalk.org/index.php?topic=167229.0
mining proxy (must compile): https://github.com/CryptoManiac/stratum-mining-proxy