1) Contact your bank and let them know you are traveling. You will likely only be using pounds and euros (unless you make it to switzerland, then francs). If you have a national bank, you should be able to use any ATM that is part of the global bank alliance for free. Get the names of the banks that belong in the countries you are going to. France is Paribas, can't remember the other countries. If you use an ATM that isn't part of it, make sure it is still a Bank ATM, the typical charge is 1% transaction fee and a $5 fee. For me, I have found it to be cheaper to pull out money if I am pulling out more than about $250. If it's less than that, then it's cheaper to use my debit card which is only %3. Do not exchange money. You will get raped in fees. Also, keep in mind that most debit cards here are chipped, you sometimes need to tell the clerk that your card needs to be swiped. Also, some machines will only take chipped cards so it's good to always care a small amount of cash should this happen to you. I got caught at a $36 toll driving in France and only had $12 euros on me... Caused a huge line of traffic and had to go into the transit station and pay by card.
2) Cell phone/Internet. If you have ATnt or Tmobile, you can use your phone here. Call the phone company and let them know you would like your phone unlocked while you travel abroad (AT&T may not do this if you have an Iphone). If you have Sprint or Verizon, your shit out of luck and will need to buy a phone. Orange is the biggest network, I bought a $20 sim card, I pay 10 cents per minute in Switzerland for calls I make and 10 cents per text for texts i send. Incoming is free. If I leave the country, it's 60 cents per all texts and $1.20 per minute for all minutes. So it may be cheaper to buy $10 sim cards for whatever country you are in. Also, a LOT of the major cities out here have free wifi. Paris has like 250 hot spots, London has them all over the place.. Pretty much every city I have been to offers free internet to an extent. So buy a phone card with no internet or extremely limited and disable facebook and all that and only use it for google if you need to look up a location.
3) Public transit. I bought a Eurail Pass, this can be a good deal, or not. If you plan to make longer trips, it's a good deal. I'm paying an average (after additional fees) of about $100 per trip and can make them with little to no notice. Flying can seem cheaper, but the train tickets to get to the air port, the hassle of being at the airport, needing to book so far in advance... all becomes a pain in the ass. Flights are only cheap if you know far in advance you will be taking them. Trains are only cheap far in advance as well. With a Eurail ticket, they are just the 1 price and you pay for your reservation. Some reservations are cheap, sometimes they aren't needed, and some cost more. If you get a first class eurail pass like mine (which I so highly recommend, they feed you and give you free drinks) you are looking at around $100 per major trip like mine. Second class you'll probably be closer to $60 per trip.
Also, consider the eurostar between England and Paris, I know that the flights are cheap, but if you get a Eurail pass, I believe it's only $100 round trip in which you go straight from the center of London to the Center of Paris. Both the Airport in London and Paris are a bit far from the city and you can end up paying $15 for just the train to the aiport. So it really begins to add on fees. And with the train, there is no baggage allowance, customs is silly and almost non existent, and you show up half hour in advance, it's so easy.
4. explained in #1
5. Hostels, you should try to book ahead, different events make things more expensive. Hostels in Munic over oktoberfest are around $100 -$200 a night when they are typically $20. That being said, Couchsurfers.com is the shit. I trust it pretty well, have had people crash with me while living in Luzern who have had next to no difficulty traveling europe with no lodging costs. Just buy your host a bottle of wine or make dinner and you are set. Keep a small emergency fund should you make a last minute decision and need a cheep hotel/hostel.
6. I will be in Switzerland till September 20th, then Germany till the 26th, then Annecy for IF3 and I fly to Iceland via Paris on the 1st.