Hi I have gone and bought an old tutorial that is exactly what I need to learn for a project…But it was made in 2005!
Only just realised.
Will I have a problem trying to translate between the previous zbrush editions and now?
That sounds as if it would be for ZBrush 2. It depends what the tutorial is about - a lot has changed on the UI and sculpting side since then - but there will be some that is still relevant.
Yes, it is ZBrush 2.0. No subtools, no polypaint, no Brush palette, no HD geometry. 
A lot of what Aaron says will be relevant in a general way. You can load the alphas and use them with the Standard brush to use his approach.
Oh dear…well I suppose I will have to ask more daft questions when they arise 