Difference between DOHC and SOHC VTEC

[ahcash]

Was reading these and it has very good explaination of DOHC VTEC and SOHC VTEC (like the one on Jazz?) And what the hell is VTEC?

DOHC VTEC
www.leecao.com/honda/vtec/dohcvtec.html

SOHC VTEC
www.leecao.com/honda/vtec/sohcvtec.html

What is VTEC?
www.leecao.com/honda/vtec/whatsvtec.html

TOVA special technical feature Honda's new L-Series Engine
asia.vtec.net/Series/FitJazz/lseries/index.html