There are four torx-headed fasteners (T15 I believe) along the top of the dash, just like 3XBrownCutty mentioned.
Remove your instrument bezel, and the gauge cluster, so you can unhook the speedo cable. If your car has/had cruise control, you can unhook the cable under the hood, to allow it to pull out a bit more so you have easier access to unhook the cable and VSS thing.
There is a 13mm bolt on each lower corner of the dash, fastening it to the sides of the cowl.
Loosen your steering column. The dash frame is sandwiched in between the column and the column support.
Unhook your parking brake release cable.
Remove you stereo any unhook any extra wires.
Remove your HVAC controls from the dash, and just let them hang. They will slip out the back as you remove the dash.
There is another 13mm bolt hiding along the bottom of the dash, kind of behind the radio, to the right.
You'll then either have to disconnect the wiring harness from the bulk-head, or dick around with a bunch of 7mm fasteners that hold the wiring harness in place along the back side of the dash. If you're planning on leaving the harness in the car, then you'll have to unhook each component, like the defrost switch, headlight switch, and anything else in the way.
After that, it'll pop right out.
It sounds like a lot of work, and I was kind of intimidated by the task the first time I undertook it, but I've had a couple Cutlass dashes apart now, and it's not too bad of a job.