Hi All,
Fay actually found this piece of software called DeepSkyStacker for aligning & stacking DSLR raw images. I've been playing with it & seems to work really well - It's very automated & easy to use - a whole lot more user friendly then IRIS. I for one will be using in future. S/W is free & can be downloaded from here:
http://deepskystacker.free.fr/english/
I did a quick stack of some raw files I took of M27 in June using my EOS 300D & WO ZS66 - alignment looks really good..
Cheers, John
(http://homepage.ntlworld.com/john.punnett/graphics/oas/m27_dss1.jpg)