Jon Peatfield said...

|If you just want to add extra packages for the install then you can do 
|that just creating an extra 'yum repo' and pointing the sl5 installer at 
|it in addition to the standard ones.
|
|Then either with kickstart or a semi-manual install you get to see the 
|extra rpms in all the repos you have listed - and you can specify your own 
|groupings if you care to write a suitable comps xml file...
|
|Any other customisations can be done by a script (for kickstart) or extra 
|packages containing the magic (if you want to support manual installs).
|
|I guess if you want to make custom ISOs you need to arrange to either add 
|the extra repo into existing ones, ship an extra ISO of your repo or just 
|point them at a network accessible version.
|
|Keeping your own repo(s) of extra packages is handy for doing yum updates 
|from later anyway so you probably need that anyway.
|
|What else do 'sites' offer?

That's fine until you start using a different version of
a package than the vendor uses.  Maybe there's a way around
that in yum; I haven't really figured yum out yet.  Is there
a *good* doc on yum out there that explains such things?