hi mike
I can try to answer some of your questions as I have been in europe at this time of year.  frist to hopefully help out with some questions:
1. I always get some cash in euros (say 100) before I leave so you have money as soon as you get there and for a few days in case exchange places are closed.  It also gives you some freedom to shop around for exchange rates.  If you’re planning on being in major cities traveller cheques are good, especially if you buy them in euro and cash them in where you bought them (ex. an american express).  My ATM card has never worked in europe but that might be a bank thing.  I also usually bring a credit card with a PIN so I can use it like an ATM card and withdraw cash. One last thing about PIN is that european ATM’s only have number keypads and sometimes only accept 4-digit PIN’s so if yours is long or a word keep that in mind.
 
2. You don’t really need to pack very much.  I would definately bring a light coat such as a windbreaker or rain jacket because in some place or altitudes it can get cold in the evening and rain is not unheard of in June.  I’d check out the packing list on this forum for further advice.  It was blazing hot in paris in june when I was there and I did manage to get heat exhaustion, so if you have room bring a hat and always have a water bottle.
 
3.  I would buy a camera case (I have a lowepro one) that has extra pockets for other things (water bottle, sunscreen, hat, food, etc.).  It has the added bonus of looking just like a normal day bag/backpack so anyone inclined to steal cameras may be distracted.  It also rests on my back so when I’m somewhere where I’m taking a lot of pictures I can put my camera around my neck and can still have my bag on.
 
4.  I alwyas caryy small amounts of money and coins (< 10 euro) in local currancy in my pockets or day bag so if I want to buy something cheap I don’t have to open my money belt or dig through lots of money.  I’ve also heard that some people keep a spare 50 in their shoe as an emergancy but I never have.  Everything else is in my money belt tuck under my clothes.
 
I hope this helps and have a great trip
e

    Hey mike welcome to eurotrip. Congrats on planning your first trip however I think your being a bit ambitious in the number of countries your trying to fit in. That aside let me attempt to answer your questions point by point.
1. I would agree with the previous poster that getting a small ammount of cash before leaving is an excellent idea so you dont have to fumble around for a bank to exchange money right as you get there. Most atm cards these days are on some worldwide network (circus/plus etc..) so there isnt much of a problem finding an atm network. I would strongly advise you not to plan to use your credit cards to withdraw cash since A)You will most likely pay a cash advance fee and B) You will be charged interest from as soon as you withdraw the cash

2. As far as clothing goes it can get chilly in parts of ireland even in june so a jacket would be a good idea. Besides that you would have to give us more of an idea of where exactly your planning on going since if you end up in any higher elevation locations it could be quite a bit cooler.
I totally agree with what the previous poster said for 3 and 4! If you have any other questions feel free to drop me a pm.
cheers
howie

Everyone has made some really good points, I just wanted to add a couple other things…

As far as clothing goes, bring a little bottle of laundry detergent with you in a plastic bag, that way you can wash small things like socks, underwear, and shirts (and pants if you feel ambitious) in the sink at your hostel and then hang them to dry in your room (some people like to bring a short rope for a clothes drying rack). This way you can bring the absolute minimum in clothing, and you don’t have to spend money on doing laundry while you’re there. Also, bring things that don’t show a lot of wear, like jeans, so you can get away with wearing them for a while before the look dirty. Also, don’t pack your bag completely full when you go, because chances are you will pick up small souviners along the way and you’ll need room for them in your bag.

As far as money, I like to bring a SMALL amount of cash with me (just in case you want coffee or something when you get there), credit card/debit card (you get the best exchange rate from ATMs) and a travellers check for emergencies (while I was in Rome all the atms were down one day). Make sure you contact your bank before you leave, or your card won’t work when you get there because of theft detection systems. Also, you need to have a 4 digit pin number for your card to work in Europe.

Hopefully this was helpful, and keep posting questions on here, I’ve learned lots of useful things from the people on this site! Good luck!