Seeking a concise Linux installation checklist

[joe at actionline.com]

Even after having done several Linux installations (some a lot more
challenging than others), I am still a bit intimidated by it.

Now, I'm about to undertake another and I hope the PLUG brain trust can
provide some guidance, perhaps a concise installation checklist for this
next attempt.  I have a box with win-xp installed on a 100-gig HD and I
need the following:

1. How (most efficiently) to shrink and repartition for a dual boot with
xp on perhaps 20 gig and the rest for installing two Linux distros.

2. I've installed PCLinuxOS several times and I (by far) prefer the older
version with KDE 3.5, so I want to put it on one set of partitions using
about 20-gig.

3. On the rest, I want to install whatever Redhat based distro might work
best with Virtual Box (which I have never been able to get to work
before).
Some have recommended Cent OS (I've been told that there is a KDE 3.5
version available).

Any guidance to make this as concise, easy, and efficient as possible for
a 20-year perpetual "newbie" user would be extremely appreciated. ;)