Sounds like the same for you anarky. Check error codes, she will normally give you an error. Coil packs, dfi module, cas and ecu all tie up in the system, so if any of them fault, it can give you similar problems, but, as I said, 99 times out of 100, its going to be the CAS.
As CHANDLC said, if you can afford the $100, definatly get a mechanic, save yourself the trouble. Isnt the easiest job, specialist tools can make it that bit easier.
I remember the first time I had the CAS go, was failing when it was warm too (doesnt always do that). I would stop and get petrol, and car would not start after that. Lucky no one was behind me, so I could push the car back and wait until she would start again. Hadnt had the car all that long and I was thinking it was something to do with the fuel. I was even going to see the gf one day to go out on a day trip, stopped and got flowers and car would not start. Was a hot day too. So get it done soon, it will eventually cause the car to stall while youre driving, and you will suddenly feel the steering and brakes get really really heavy, car will drop speed and you will need to try and hit hazard lights while pulling off to the side hoping theres no speeding cars behind you. Not a nice feeling.