I've never used the installer, I just place my litestep dir in C: and use an OTS dir structure. Then I edit the registry like this: (Using a an acount with admin rights)

Navigate to the following location under the HKEY_LOCAL_MACHINE key:
Software_Microsoft_Windows NT_CurrentVersion_IniFileMapping_system.ini_boot

You see a string entry called 'Shell' which should have the following value:

SYS:Microsoft_Windows NT_CurrentVersion_Winlogon

Select this entry. When you have the 'Shell' entry selected, edit the string value and replace the characters 'SYS:' with 'USR:Software_'. The entry should now look like this:

USR:Software_Microsoft_Windows NT_CurrentVersion_Winlogon

Navigate to the following location under the HKEY_CURRENT_USER key:
Software_Microsoft_Windows NT_CurrentVersion_Winlogon

Look for a string entry called 'Shell'. If it is not there, create a string entry and name it 'Shell'. Set the value of this entry to the name and location of your shell. For LiteStep, the shell entry may look like this:

"C:LiteStepLiteStep.exe"

or wherever your LiteStep executable is located.

Then I open explorer go to Tools/FolderOptions/View and check the launch folder windows in a seperate process box.

Restart windows and bingo there I go. If I need a user with Explorer as the shell I create a new user and I'm good to go. But who uses Explorer anyways. ;) Never saw a reason for a shell switcher, if I need to switch shells quickly I could use fast user switching and log on to another account with whatever shell I feel like. Each user would have whatever shell I wanted in the HKEY_CURRENT_USER key:
Software_Microsoft_Windows NT_CurrentVersion_Winlogon_Shell="whatever"

Been doing it this way with win2k and now winxp for nearly 3 years now and I've never had a problem. Well it works for me, granted it's alot easier for the first time user to use an installer, but some of us had to do it the hard way back in the good 'ole' days. Old habits die had I guess. :)

*note "Underscores in reg entrys should be back slashes"