This is the program: http://www.canadainternational.gc.ca/united_kingdom-royaume_uni/experience_canada_experience/index.aspx
They are currently out of visas for this year so you would have to be ready to apply when they open again in the new year. If you get a visa for 2014, you need to enter Canada some time in 2014 and then you have a year from that date. In early 2015, you could apply again to get another year. This is an open permit so you do not need to find a job beforehand.
However, if you want to immigrate, you should be looking for either a skilled job in any province or a semi-skilled job in AB or BC that falls under their PNP's. To see which jobs they are, look here:
http://www.welcomebc.ca/Immigrate/immigrate-BC/Provincial-Nominee-Program-Home/Strategic-Occupations-Home/Entry-Level-and-Semi-Skilled-Workers-Home.aspx#occupation
http://www.albertacanada.com/immigration/immigrating/ainp-eds-semi-skilled-criteria.aspx#eligible
A skilled job is better because then you can apply for your immigration if you work full time for a year regardless but the semi-skilled, you'd need your employer to want to sponsor you. If you want to immigrate, you better play your cards right. You do not want to waste your two year open work permit working jobs that can not lead to your immigration. A two year open work permit is an opportunity that most people in the world do not have. It is only a handful of countries that participate in these working holiday programs and you are lucky to be from one of them.