is it best to join an agency for a second job or is it best to look through websites to find my next job. also what happens if you have experience in one thing but you want to change career?? are the skills i have developed already wasted?

I guess it all depends on your profession/career path. If you have specialised in a particular industry, profession or function, then i would follow the norm for those (e.g. finance/accountancy experienced vacancies are quite often filled via recruitment consultancies/agencies). If you have not specialised, i would probably use one of the general jobs websites like Secondpost.com or Monster.co.uk.

Paul, I reckon any skills you pick up along the way (I nearly mistyped "skulls" there!) are going to be useful in any future job, it's all grist to the mill! Trick is to be able to talk about them at interview, to let the recruiter know how they're relevant to the role you're applying for.

I think Jeff Bridges (is that your real name?) is right.  Life is about experience and the best lessons are learnt along the way, regardless of what it is that you are doing.  No matter what job you are currently doing it will have some merit in a different field.  Good luck in the hunt (and tell them I want your old job whatever it may be, anything beats unemployment!)

A lot of skills you pick up are going to be applicable to several jobs, not just a specific one. You can, in many roles, pick up teamwork skills or organisation skills which you can use anywhere!

Fully agree.  Life is all one big lesson, just be prepared to learn from it.