Well now, this can cause controversy.
Most would agree that the Ramones were there at the beginning, they formed in New York in 1974.
They played very fast, very short songs without guitar solos and used a lot of distortion.
Most would also say that Iggy Pop & the Stooges, were if not a punk band as such, were a big influence on the bands that followed, see also the New York Dolls, Velvet Underground.
In the UK, the Sex Pistols formed in 1975, different style to the Ramones but very noisy, anti-establishment types.
Many bands followed, chief amongst them , the Damned, the Stranglers, UK Subs, Siouxsie & the Banshees, Stiff Little Fingers (from Northern Ireland), The Undertones (also from Ulster), and many, many more.
The ethic was, very much do it yourself, small independent record labels, minimal marketing, in some cases not too much in way of technical skill, and above all ant-establishment.
Oh and I've just found this
http://en.wikipedia.org/wiki/Punk_rock
cheers
David