Hi,
to apply for a 121 visa you have to have been working in Oz full time for 2 years but only 1 has to be for the employer who nominate you. As far as I know you can change position in the hospital, its not the job, its the employer who provides the nomination so as long as you stay with that employer for at least a year you can move areas.
In order to apply for 457, the first step would be to register with Queensland Nursing Council. Im resgistered with the NMB NSW but Im sure its pretty much standardised. You can download the forms off the website, get all your certificates notorised, provides letters form current and previous employer, send it all off and wait the 8 or so weeks. Then find yourself a job, which is VERY easy, either go via a recruitment agency such as
http://www.profco.com/, or ring around hospitals yourself, either option is good. Once you get the job offer they will provide a nomination letter which has your nomination number on, then fill in your online application at:
http://www.immi.gov.au/skilled/skill.../sbs/index.htm, this takes all of 3o mins to do and you will get a response, usually within 4 weeks, although I have heard that there have been delays of up to 8 weeks just recently. During the wait find yourself somewhere to live, this is a good place to start:
http://www.realestate.com.au/.
Book your flights and your away!
Working here is great, work practicies are much like in the UK, the people are very helpful and friendly. We are in Sydney, which is considered an expensive place to live, and yes the quality of life is overall slightly better than in the UK. The weather certainly helps too. I would say that financially I am slightly worse off here, but the lifesytle more than makes up for it and if we were to buy rather than rent then the type and size of house that we could get would be way better than in the UK. Anything else I can help with dont hesitate to ask.