Power chord for use in USA

[jumbles1971]

I want to take my laptop on holiday to the US but don't know where I can get a mains chord for it. My PSU is a VGP-AC19V16 and the chord has a 3 hole female end that plugs into the brick. From what I understand, in the US they only use 2 pins so do I need to get a cable with all 3 holes or will one with just 2 suffice?

Hopefully someone will understand what I'm on about.

thanks
Jumbles

[Blencogo]

Probably one of these will do?

http://info.maplin.co.uk/Module.aspx?ModuleNo=11645&&source=14&doy=9m11

[jumbles1971]

I thought about using an adapter but wasn't sure if it would be safe to leave it connected like that for long periods of time. Is it?