Every time I try to install BT on a Virtual machine, I mess up the steps. So here is the relevant section from the site below.
Backtrack clean Hard Drive Install
This method of install is the simplest available. The assumption is that the whole hard drive is going to be used for Backtrack.
1. Boot the VM using the ISO
2. In the console type “startx” to get to the KDE GUI
3. Open terminal and type ubiquity
4. Follow the instructions on the subsequent pages and at the end click Install
5. Allow the installation process to complete and reboot
6. Login to BT using default credentials, root/toor. Change the root password
7. Fix the frame buffer splash by typing “fix-splash” ( or “fix-splash800” if you wish 600×800 frame buffer), reboot.
Also, in a Linux virtual machine, shared folders appear under /mnt/hgfs, just in case 🙂