He is the method of installing .deb files using the Terminal using standard linux commands:
Installation using the Terminal
- Go into Settings -> Security -> Developer Mode and then Enable “Developer Mode”
- Go into Settings -> Programs -> installations)
- Launch the Terminal Application
- Enter ssh root@localhost (standard linux ssh command)
- When prompted for a Password, Enter rootme (Default Nokia N9 Password)
- Enter dpkg-i filename.deb
For information on .deb files, please see the Wiki Page