What should I do with Travellers Cheques I have in the national currencies to be replaced?

Travellers Cheques are valid forever so you will not lose out in any way. If you are in Europe you will be able to change them for a short period at commercial banks and for a far longer period at central banks (see 'How long will the changeover period last?' for more details.)

However, for the sake of convenience it is strongly suggested that you change or use any Travellers Cheques or other money that you may have in the national currencies to be replaced as soon as possible. Changing them in third countries may well prove difficult and you would need to check with national banking authorities if it would be possible.

What will happen to any bank accounts that I hold in any of the currencies that are going to change to the euro?

If you hold a bank account in Deutsh Marks, French Francs etc., your bank should have contacted you with regard to the change over. Generally, these accounts would be converted to euro but you should check with your bank.