Upgrading and selling my MacBook, how do I clean install Lion and iLife?
If you want to sell your machine but also include installed software, there is a way to set this up that will ensure none of your personal data is on the machine, as well as provide a better box opening experience for your buyer.


I would suggest doing a secure erase of your hard disk first. Then, install Lion.
Configure a dummy user account named "test" or "admin" or something generic
Install the software you want to include
Restart your machine in Single User mode by holding &#8984; + S on startup.
Very carefully, do the following:



  mount -uw / (This mounts the root volume so you can make changes to
  it.
  
  rm /var/db/.AppleSetupDone (This removes the flag that tells Setup
  Assistant that it's done)
  
  rm /var/db/dslocal/nodes/Default/users/"shortname".plist (Replace
  "shortname" with the user account name you set up before. This removes
  the user plist)
  
  rm -rf /Users/shortname (Replace "shortname" with the user account
  name you set up before. This removes the User directory)
  
  rm -rf /Library/Preferences (This resets preferences)
  
  shutdown -r now (This restarts the computer)


Verify that your machine starts up to the Setup Assistant and you're done. That way, your buyer can start up the machine to the Setup Assistant and still retain the software you want to provide them with.

Good luck.