Confusion with Converters

I live in Los Angeles and I'm traveling to London, I need to plug in my mobile phone. Do I need a converter and an adapter, I'm seriously confused. I found a site that sells them, but the site isn't very user friendly. Cheers. 

I think for a mobile you can just get away with an adaptor (for the plug).

Depends.

British electricity is 230V AC your charger should say what voltage it accepts.

Thank you for helping me, I just got my phone and it came with an international plug.

The fact that it was supplied with a multi-configuration plug doesn't necessarily mean that it will accept different supply voltages as well.

Check the listed voltages on the charger label.   You're looking for a line which says something like "120V 60Hz" or -- more helpfully in your case -- "90 to 250V 50/60Hz."

If your charger isn't 50-60Hz/110-240v, and it's a big name phone (Nokia, Sony Ericsson, Motorola, etc) you might be better off just getting a UK charger here from one of the ubiquitous mobile phone stalls on every market.