how hard is it changing the head gasket on a 1.6, 8v, MK 4, Astra?

Have a water leak on the head gasket on a 1.6, MK 4, Astra
Is it a hard job to do as i have limited skill, of is it easyer just to take it in to pros. Up intill now i have done all the work on the car when needed, as it is an R reg car, and i hate paying someone to fix something i can do.
Any tips, or help would be great thanks,
Ross