While in the U.S. its best to set up a job before entering Europe, but for the fun jobs, you'll have to go to a recruiter or website listing jobs. If you are in Europe already, the job search can be done by networking in the hostel lounge area, to strolling aimlessly through the city looking for western style restaurants, to stopping into a recruiting office and asking for any jobs that require English speakers. Job opportunities are everywhere, but if you find a job this way, the pay is usually "under the table" and there's no real security with this type of employment.

I found my first part time job in Vienna, Austria by being at the right spot at the right time, and ironically it was one of the few times i was dressed up...When the employer walked into the lobby at my school in downtown Karlsplatz, he said he immediately noticed that i was dressed better than the other students and decided to test me if i knew German or not. Basically, my 3 years of German classes paid off and I was hired on as a representative for his Art dealership. I had a blast! We would drive around town and deliver artwork to companies, pick up the money, set up art shows.

My second part time job, I found through a friend, working security at a Club in downtown Vienna. It was a two level club with bars on each floor and a really laid back atmosphere with dancing and lounge areas.  We got paid each night at the end of the shift in cash.

All in all, I had an incredible time and it was a blast working in a foreign culture. My suggestions are to find a job before you get over there or at least get some contacts, dress up, and learn some of the language...you'll be assured to find work.