Sirbibble- cool name
I wouldn´t do the agent thing. Too much money has been scammed from students doing the same thing. I´m sure ther are legit agents, but still, you´re better off walking in to Irish pubs and hostels to search for work under the table. Or, if you have a work visa, your stock just went up.
Check out Thegumtree.com
for listings on possible jobs. This board is popular with Australians.
An up and coming site along the same lines is- http://london.craigslist.org/
Monster has a UK site- http://www.monster.co.uk/
and, under the "work" forum, there´s a link for how to get around by being a bartender. That might stir up some options for you.
When you´re in Europe, strike conversations with students at the internet cafes. They can often point you in the right direction.
For now, work double time to build up your cash reserves and go easy on you funds in Amsterdam and London- 2 expensive cities. Clubs can get quite costly with entrance fees and drinks that can be $9 each(normal price at some clubs in Madrid).