Every theme needs lsxcommand so it's included of course. Known as the "swiss army knife" of Litestep modules, you can activate bang commands and do internet searches in it among many other things.
The winamp controls are provided via the use of Dynamp. It will detect which version of winamp you have (2 or 3), and works with either version. Lsxcommand provides the winamp text display.
Lswchanger loads the included wallpaper with this theme, automatically detecting the correct screen resolution. If you'd rather not have this feature you can disable it quite easily.
Open up the theme-step.rc and browse down a few lines to: "LoadModule $ModulesDir$lswchanger.dll". Just place a comment in front of the line like so: ";LoadModule $ModulesDir$lswchanger.dll" and save the step.rc.
Recycle Litestep and the wallpaper module is disabled.
Taskbar3 is used to display the open tasks. Taskbar3 appears in the bottom bar.
Mzscript is the premier Litestep scripting module and runs "behind the scenes", enabling advanced functions like the bar toggling.
bPopup is used for the "Launch" menus. It allows the menus to use different graphics and settings than the main popup.