I took a gap year to give myself a break from
academia for a short period. I knew all along
that what I wanted to do (free from the stress
of essays and exams) was go and work on a campsite in Europe: in my opinion being a campsite courier is the most accessible way of doing it.
Definitely the most important skill necessary when applying is customer service experience. Companies are very unlikely to take your application seriously unless you have at least three months experience in some shape or form of working with the general public. This is because customer service is a crucial part of life as a courier: you are essentially the stop-gap between the customer and the company they booked their holiday with.
Many people get overwhelmed at the thought of being a courier because of the common misconception that you must be able to speak a foreign language. This is not a pre-requisite but a definite bonus if you can.
The first step is research: look up companies themselves as well as forums for seasonal workers. This will give a good idea of what's out there as well as what the company wants from you and perhaps most importantly, what it's really like to work for them. Don't forget though, everyone is different so don't be put off because someone says that one company is awful or because they had a bad experience ... you never know the full story behind their comment!
After research comes applying: a lot of companies have online application forms, so before you fill it in think about
What position you are applying for i.e. courier, children's courier, courier in charge.
What dates you are available to work. You should find that the companies are flexible, to a certain extent.
What you want to say and how you want to come across.
You will probably hear from them by letter and normally within a week or two, depending when you apply. If you're lucky you will be invited for an interview. And then if after that you are offered a job you will be told where and when you will leave for training. Each company does its training in a different place and a different way, for example Holidaybreak (the company behind Keycamp and Eurocamp) now have an online training course and then on-site training once you are at your *area *. Canvas, however, provide on-site training or intense training at a site near to Paris.
Have a look at my jobs page for links to a few companies.