Due to the recent Reg changes regarding Opt-In for ATM/Debit card transactions, if our bank decides to start offering an Overdraft protection service that customers can Opt-In to, does that OD protection amount have to be disclosed in online banking and if so, does it have to be distinguished from the current or available balance?

See section 230.11(c) of Reg. DD.

http://www.bankersonline.com/regs/230/230-11.html

Here's the FRB's Official Staff Commentary to this section.
(c) Disclosure of account balances

1. Balance that does not include additional amounts. For purposes of the balance disclosure requirement in section 230.11(c), if an institution discloses balance information to a consumer through an automated system, it must disclose a balance that excludes any funds that the institution may provide to cover an overdraft pursuant to a discretionary overdraft service, that will be paid by the institution under a service subject to the Board’s Regulation Z (12 CFR part 226), or that will be transferred from another account held individually or jointly by a consumer. The balance may, but need not, include funds that are deposited in the consumer’s account, such as from a check, that are not yet made available for withdrawal in accordance with the funds availability rules under the Board’s Regulation CC (12 CFR part 229). In addition, the balance may, but need not, include funds that are held by the institution to satisfy a prior obligation of the consumer (for example, to cover a hold for an ATM or debit card transaction that has been authorized but for which the bank has not settled).

2. Additional balance. The institution may disclose additional balances supplemented by funds that may be provided by the institution to cover an overdraft, whether pursuant to a discretionary overdraft service, a service subject to the Board’s Regulation Z (12 CFR part 226), or a service that transfers funds from another account held individually or jointly by the consumer, so long as the institution prominently states that any additional balance includes these additional overdraft amounts. The institution may not simply state, for instance, that the second balance is the consumer’s “available balance,” or contains “available funds.” Rather, the institution should provide enough information to convey that the second balance includes these amounts. For example, the institution may state that the balance includes “overdraft funds.” Where a consumer has opted out of the institution’s discretionary overdraft service, any additional balance disclosed should not include funds institutions provide under that service. Where a consumer has opted out of the institution’s discretionary overdraft service for some, but not all transactions (e.g., the consumer has opted out overdraft services for ATM and debit card transactions), an institution that includes funds from its discretionary overdraft service in the balance should convey that the overdraft funds are not available for all transactions. For example, the institution could state that overdraft funds are not available for ATM and debit card transactions.

3. Automated systems. The balance disclosure requirement in section 230.11(c) applies to any automated system through which the consumer requests a balance, including, but not limited to, a telephone response system, the institution’s Internet site, or an ATM. The requirement applies whether the institution discloses a balance through an ATM owned or operated by the institution or through an ATM not owned or operated by the institution (including an ATM operated by a non-depository institution). If the balance is obtained at an ATM, the requirement also applies whether the balance is disclosed on the ATM screen or on a paper receipt.