How do they check references? And do you need a police certificate?

I'm not really sure how getting a job even works in the uk (on spouse visa)...are most employers able to contact your former US employers, or is it too tricky because it's international? Would it be better to ask my employers in the US for letters of reference BEFORE I go across the pond to make it easier for employers in the uk?

And if I need a police certificate for whatever reason, is that something Americans can obtain somehow? I've never heard of it before and wouldn't know where to start!

I would imagine prospective employers would contact your referees by email, wouldn't it be the same in the US?

I can't help with the police certificate question but CRB (Criminal Record Bureau) checks are carried out for anyone who wishes to work with children, the elderly or individuals who might otherwise be classed as vulnerable.

And if I need a police certificate for whatever reason, is that something Americans can obtain somehow? I've never heard of it before and wouldn't know where to start!

Yes. They can run CRB checks on Americans. I had one for my first job and I had no problem getting it. I just filled out the form given to me after accepting the job, my employer took care of it submitting it and I received it in the post a week or two later - the employer gets their own copy in the post so there was nothing I needed to do with it besides keep it in a safe place at home.

edit: Sorry - didn't realise police certificate was different from CRB. See ksand's answer below.

And if I need a police certificate for whatever reason, is that something Americans can obtain somehow? I've never heard of it before and wouldn't know where to start!

Yes, it's definitely something Americans can obtain - I'm British but lived in the US as a student for a while and when I got my current UK job, I had to go through full government security clearance and was required to obtain a police certificate from the US. If I remember correctly, it involved printing a form from the US police website, filling it out and mailing it to the US (and possibly including a check for the certificate).