CentOS 6 Running Out Of Space

Error message: At least 2MB more space needed on the /boot filesystem.

rpm -qa | grep kernel
Resulting grep:
kernel-2.6.32-71.el6.x86_64
kernel-2.6.32-71.29.1.el6.x86_64
kernel-2.6.32-131.0.15.el6.x86_64

Newest one is 2.6.32-504
Remove all except the most recent one
rpm -e kernel-2.6.32-71.el6.x86_64 kernel-2.6.32-71.29.1.el6.x86_64

Update kernel
yum -y update kernel

Update other things (optional)
yum -y update

Reference: http://www.cyberciti.biz/faq/installing-kernel-2-6-32-131-2-1-el6-x86_64-needs-8mb-on-boot-filesystem/