update redhat kernel

[htc sun]

Hi ALL,

I'm new to redhat. I have a system and can someone share with me where can I
download and install the kernel update? The kernel version for my system
is:-

# uname -a
Linux redhat-04 2.6.18-92.el5PAE #1 SMP Tue Apr 29 13:31:02 EDT 2008 i686
athlon i386 GNU/Linux

Also, I have a repo server consists of all the packages. How can I install
the dovecot, httpd and vsftpd packages etc on this system from my repo
server and how do I take care of those packages dependencies.

Regards,
htc