Curency in IRE
 

can i use british puond while traveling through IRE?

How frequently will I find ATM (Money vending machines) while traveling through IRE?

No, you'll need Irish pounds (approximately the same exchange rate), and I don't know about ATMs. I wouldn 't count on them except in the large cities (Dublin, Galway, Cork), perhaps.

ATM's are common throughout most of Ireland, including the samller cities. I found that the "star" and "cirrus" system links are popular, but some of the more common USA systems are inaccessable. You will not be able to spend your UK pounds in IR; you'll need Irish punts

ATMs won't be a problem for you in Ireland. Most accept Visa and Mastercard, American Express to a lesser extent. I think you'll probably be limited to a withdrawal of 160 Irish punts per day. Just check with your lender before going to make sure you have a PIN, and that it is activated. From what I saw on a recent trip, Mastercard is the card most widely accepted in Ireland.

ATMs are common throughout Ireland (N and S), and any bank will change UK to IRL (I don't remember
the charge and so it must be small). Businesses
will often take UK at a discount. Visa and
Mastercard are accepted almost everywhere, and
Amex in some places.

Do most banks in England let's say Milton keynes
which is north of London-do most banks exchange
British pounds to irish pounds?

ATM's are VERY common in Ireland. Most tourist areas will have an ATM accepting credit cards, Eurocheque cards and Cirrus.
You can convert sterling or dollars into Irish pounds at most banks or bureau de changes. The airport banks have late opening hours but charge more. Usual bank opening hours are 9-4 Monday to Friday, late opening Thursday til 5pm. Private bureau de changes will be open outside these hours but they'll charge more also.
Sterling was widely acceptable in shops in Ireland until the British pound fell a few years ago. Some shops might accept notes, but most don't like to because it's worth less than the punt. Coins similar to Irish will be accepted, but not pound coins.
Enjoy your trip!