They can be found in front of Doc Mitchell's house in Goodsprings.

This mod adds VenturianTale's followers from Fallout 3 into Fallout New Vegas. Venturian requested a follower mod, so here it is.

Quasar
Timebomb
Sentinel Sarah Lyons
Copper II

I recommend using this mod for the red bug eye glasses for Timebomb http://www.nexusmods.com/newvegas/mods/36333/?

Installation:
Use Nexus Mod Manager
OR
Drop the file(s) in your C:\Program Files (x86)\Steam\SteamApps\common\Fallout New Vegas\Data folder and activate