[ThomasPowers]

You can of course find mention of smithing in the Triads:

Three things that are best in the world:
the hand of a good carpenter,
the hand of a skilled woman,
the hand of a good smith.

Three sounds of increase:
the lowing of a cow in milk;
the din of a smithy;
the swish of a plow.

Three holidays of a landless man:
visiting in the house of a blacksmith,
visiting in the house of a carpenter,
buying without bonds.

Three things that constitute a blacksmith:
Nethin's spit,
the cooking-hearth of the Morrigan,
the Dagda's anvil.

Three things that constitute an artificer:
weaving chains,
a mosaic ball,
an edge upon a blade.

Digging into the Brehon laws should prove interesting

There are several books on Irish Archeology that mention ironworking in them as well; I will try to find some cites in my library

And of course the "dog of Culann" and that story showing the place of the smith in early Ireland.