Is it sufficient to provide a link to the Reg E error resolution language or does it need to be included in an email to the customer?

Interesting question. 1005.8 says that you must "mail or deliver" the notice and being conservative I would say that means the notice itself and not a link to it. If the delivery is in your internet banking system and E-SIGN is compliant, "click here for your notice" may be deemed making it available more than delivering it, and even though I think that is a fine line, I'd rather provide the notice with all its content than a link.

I haven't seen an opinion on this. In many cases it is allowed to make a disclosure a link away (think Reg Z), but that isn't specifically applicable to Reg E that I know of.