Julian Cope presents Head Heritage

No. It has the same roots as 'feckless' meaning weak. Feck means strong or firm. It's just handily interchangable with fuck and Father Ted made it popular. It was originally just a way of not saying fuck in a Catholic country. It's as inoffensive as flipping or flamin' really. The offense is all in the ear of the hearer. It's a bit like smeg in Red Dwarf, although that does have rather unpleasant roots.

There's a place just north of Dublin called Termonfeckin, which makes me giggle.

http://en.wikipedia.org/wiki/Feck