[CentOS] CentOS (2.6.9-42.0.8.ELsmp) and CentOS (2.6.9-42.0.8.EL)

List,

I am experimenting with a Dual processor Supermicro and plan to use
CentOS 5 when it is released.  In the meantime I have installed Centos
4.4.  Sorry for asking such a basic question but what is the difference
between CentOS (2.6.9-42.0.8.ELsmp) and CentOS (2.6.9-42.0.8.EL)  Both
kernels have been installed, but I have not been able to find which one
is best to use for what purposes.

Thanks,

Greg Ennis