Can somebody tell me what style guitar sound Coldplay uses?

I'm not sure really how to explain this. It just sounds different from many other groups. I'd say particularly the beginning of "Talk" and "Shiver"

You're right, it sounds like U2

im sure they use an echo pedal for the guitar, to get that sound. the first time i heard coldplay, i swore it was U2, because of the echo-y guitar (which is a u2 trademark, of cource), so i dont know what to call the style (echo-y???) but i know they use something an echo pedal.

yeah, not many groups have that sound, but coldplay ripped off that echo guitar style from The Edge

Can't speak as to the exact style, but thier guitarist sure owes a lot to David Gilmour and The Edge. He sounds like He was dug from them with a spoon.
That's part of the reason Coldplay is one of the very few new bands I like

I think in the song "Talk" it's not so much the type of guitar, but what pedal or effect they use for it. Truthfully, I'm not really sure what kind of electric guitar they used for either of those songs.