How can I change the colours of a logo?

Hi there!

Thank you for reading this…

I’ve got some logos to put on a client website so I got all the images from their sites but they all have different coloured backgrounds etc.

I was just wondering, how do I go about changing the logos so they all look the same - like the ones on this example http://www.listercars.co.uk/images/partners.gif - except I want a white background with grey foregrounds.

Thank you very much and I hope to hear from you.

Take care,

Mark