NB: Ripped (and modified) from : http://tredosoft.com/comment/reply/37
How to install TrueCrypt 4.3a on Fedora 7

We are going to compile TrueCrypt from source so first grab TrueCrypt’s source code. When it’s downloaded, extract the source code and navigate to the Linux folder :
tar xfz truecrypt-4.3a-source-code.tar.gzcd truecrypt-4.3a-source-codecd Linux
Truecrypt needs to compile a kernel module during the [...]

This was modified for the instructions given for 4.2 from the (German) blog at http://fedorawiki.de/index.php/Truecrypt
Set up yum
# yum install yum-utils# yum install rpm-build redhat-rpm-config unifdef
Install Kernel Sources
This install the sources from the rpm downloaded into the current directory. The rpm can be discarded afterwards.# yumdownloader –source kernel –enablerepo core-source –enablerepo updates-source# mkdir /usr/src/redhat # [...]

This was wholesale copied from the (German) blog at http://fedorawiki.de/index.php/Truecrypt
Set up yum
# yum install yum-utils# yum install rpm-build redhat-rpm-config unifdef
# yumdownloader –source kernel –enablerepo core-source –enablerepo updates-source
Install Kernel Sources
# mkdir /usr/src/redhat # due to packaging problem, I guess# rpm -ivh kernel-$(uname -r).src.rpm
# cd /usr/src/redhat/SPECS# rpmbuild -bp –target $(uname -m) kernel-2.6.spec
Copy dm.h into the right place
# [...]

Added scripts for Linux so that the CLI options were automatically correctly chosen. The GUI on WinXP is nice, but become repetitive after a while.
mount-fieldstone :#! /bin/bashtruecrypt –user-mount /media/1GB/Fieldstone.truecrypt /media/Fieldstone
umount-all :#! /bin/bashtruecrypt –dismount
Also, so that normal users can mount and dismount truecrypt drives :# chmod u+s /usr/bin/truecrypt

Anaconda bug had i586 kernel being installed on Dell 600m laptop, with uname -a mis-reporting an i686 installation.
i586 -> i686 kernel change required, then truecrypt modules on farm.repo work like magic.
When installing packages with kmods (e.g. the rt2500 and truecrypt drivers) you might run into trouble like this:Transaction Check Error: package kernel-2.6.18-1.2798.fc6 is [...]