Design is quite simple and employs regular parts and components but you are free to change/modify it in way you like.
At first prototype I used blank DVD as reflective material but later I discovered more practical way. Technology of making FS mirror is described in my articleDIY Front Surface Mirror
Originally I'm very lazy man so I've chosen programmed microcontroller PIC18F1220 (can be replaced with PIC18F1320) to handle routine job.
PIC implements 3 channels PWM generator.
Actually it's the same engine as one I used in my IKEA light project
just code is adopted for PIC18.
PWM signal toggles MOSFET transistor 2N7000 (Id 200mA). Mirror actuator is connected as load to MOSFET.
As mirror actuator I used 5V 200mA CPU cooling fan. It's easy to mount mirror on its flat side.
Device accepts 5V and 12V fan with maximum current 200mA . Voltage is selected by jumper.
Green laser pointer is rated at 3V so I've made LM317-based voltage regulator with adjustable output.
Cheap 5mW green laser module: http://www.dealextreme.com/details.dx/sku.10094~r.32746761
What else will you need?
Dozen of resistors and capacitors, potentiometers, toggle switch, power jack, prototyping board, box of proper size and power supply unit.