OANDA.com or XE.com are useful in my experience. Note that they quote retail (among other) rates which may just be indicative (i.e. assume certain margins/charges). I don't know of any consolidate list of retail rates of offer locally (i.e. in Ireland).
Thanks Clubman. Yes it certainly would be useful to have a website where you could check exchange rates of the banks in Ireland. Thanks for those links though.
If you open an account with xe.com you can get the actual and retail rates so you know exactly what margin they charge.. E.g. last week EUR/DLR was 1.319, they were selling at 1.310
You can get a market commentary from Anglo Irish Bank e-mailed to you every morning with a list of euro rates for all major currencies. For the credit card rate, add 2% and the cash rate add 4%. They don't try and sell you anything or send anything other than the daily commentary. You'll get an e-mail every morning at around 9.