As it's a CentOS kernel, then the elrepo.org coretemp module will work just fine and will give you nice accurate thermal data for the cpu.
Does anyone know where I can find the kernel source for coretemp which does *not* depend on Xen and a PAE kernel, i.e,. other than the source RPMs from elerepo.org? I'm running a 2.6.18-128.1.10 kernel on a netbook (Intel Atom N270.)