backpacked across europe for 4 months back in 2000.
Depending on how long you are going, get a euro rail pass, and a Frommers, Lonely Planet, Rick Steves (insert other choices here) Guide to Europe.
the popular hostels require reservations a couple days in advance, during the busy season others require more time in advance. communication is not an issue (wasnt for me) i can speak decent spanish, a touch of french and a touch of german. I survived fine.
Do not over pack. I had enough clothes to last me 4 days iwth out laundry. Cargo pants that can be turned into shorts, 'dressy kahki' pants, swimming shorts. then a couple t shirts, 7 days worht of clean underwar and socks and 3 shoes.
there is tons and tons of info when i was reseraching back in 99 and 2000, so there is probably 2x as much.