I have recently installed BackTrack 3 Beta without any problems at all.
After that you will see there's a few things to update, such as slapt-get (repositories).
Also keep in mind some libs might be missing, so you gotta download and install those
as well if you intend to like me, use it also for image editing
But generally yes, the installer works. (i use ATA-HD's ,AMD CPU, SD-RAM & more old stuff .)
Though to get a little better performance i had to install the nvidia-drivers myself
of course. That was a tiny problem first due to BT 3 Beta does NOT have the Kernel
sources, but don't worry!
On the BackTrack Wiki Page: BackTrack Wiki
You can downlload the Kernel Sources so you can compile and install f.ex. nvidia drivers.
The only strange thing i don't know why is happening, is i can't watch video's properly
in BackTrack 3 Beta with NVidia Drivers, Adobe Flash Player 9, and up2date firefox.
Still with those i apparently can't see video's properly in BT3 Beta, but i'll try see if i
can fix that sometime.