Yes it works with the pearl. In fact it works with any existing BlackBerry that runs OS 4.0.2 or above. (4.1.xxx, 4.2.xxx)
Both programs make use of javaloader.exe, a command line tool from RIM that actually does the screenshot and writes a bmp file to disk.
BBScreenShooter picks up the original bmp file, displays it, copies it to the clipboard, adds a colored frame to it, re-sizes it and saves it as jpg or png if needed. It is able to auto-number files with the same name and therefor eases the creation of documentation. It comes with a small integrated picture viewer.
BBScreenStream contiguously creates screenshots, places them in the clipboard if needed and displays them on the PC screen. It allows on the fly resizing of the displayed screen and the creation of video clips. This is useful if you do a presentation and like to show the BlackBerry screen on the projected big PC screen to the audience or if you create self-help step-by-step documentation.
Hope that helps