Prob depends on yourself... I've picked up bits and pieces here and there, and have a few at home I could ask questions of if I get stuck so I'd prob have a go at it, but there's prob. a bit to it.
For one, I'm told that you should replace the head bolts rather than reuse them. I've seen some of those guys shear (not mine luckily! ) because they were reused, and when the pressure was reapplied to them they gave up.
I think its things like that that could give you problems you wouldn't be expecting/think of besides.
So, if you have guys you can give a call to if you get into trouble, and can possibly do without the car on the road for a few days, why not give it a go, but otherwise it might be worth the few €€ to get a professional to do the job.
Disclaimer - if you do have a go and it goes wrong don't blame me!!
hth,
Kev.