UPDATE: this tutorial has gotten a lot of attention since i posted it 2 years ago.. so i decided to update the information, add information and even a nice video tutorial by ~andredk which is a little long, but very detailed. i updated the old journal and submitted a new one for good measure
VIDEO TUTORIAL

installing litestep is not a big deal. it has dependencies like any other application, and without them it will error. assuming your system meets all the requirements right now you can stop reading this and install litestep using the Omar Installer. (omar is the guy who created the installer) litestep was built using the x86 architecture so a x86 system is a prerequisite, however people have managed to install and use litestep on x64 systems.  

before you install litestep on any system you need to be sure you have the microsoft Visual C++ runtimes installed. just install all the redistributable packages! save yourself some headache. 2005 2008 2010
afaik litestep has noting to do with .net, but its probably a good idea to install 2.0 and 3.0

if you're on XP congratulations! use Omar's installer or LOSI (i've never successfully setup litestep using LOSI.. then again i only tried once )

if you're on Windows 7 these 3 additional steps are important.

(1: ) if you have installed LOSI (and litestep gives you errors) remove it. install litestep using the Omar installer found here [link]

(2: ) upgrade your litestep files to litestep 0.25.0 alpha. (apparently some kind dev's hooked this up back in 09 when vista was crucified and windows 7 emerged, aero, king of super(task)bars. whatever, pft. i'm not a developer, i'm not even sure what all they did(i'm too lazy to read)but you need it)

(3: ) install jDesk version 0.74 and edit your theme.rc so that it uses 0.74. (most modern litestep themes use jdesk 0.73 <<this was true.. 3 years ago.) if you get a modern theme that uses 0.74 it should download and install 0.74 automatically, but if you're using an old theme on windows 7 edit the theme.rc

that should do it. use the utility to set litestep as shell and reboot. if you need any extra help feel free to shoot me a note and i'll help if i can

xPaintClass is modern litestep. we all use the xmodules particularly xLabel, to design litestep interfaces. the modules are amazing. very easy to configure and use. if you download a modern litestep theme you will need to install xPaintClass so that the xmodules can do their thing. follow the link for information. xPaintClass is just a dll. no big deal. the difference between it and basically every other module is that xPaintClass goes in your root litestep directory, not in the modules directory. and that's it! drop that dll in the litestep folder, and load a theme.