How do I get a Job in US,UK,Australia & New Zezland?

I am Diploma holder in Automobile Engineering having 12 Yrs of Experience

The best advice I can give u is on Australia. Ofcourse u need to have research on employment sites to see opportunities.
First of all you need a visa to be in the country. A permanent Residency gives u 5 yrs stay. Otherwsie u need to be sponsored by some company for a work visa. It is rare to be offered employment otherwise.
For the PR you first need to get an assessment done - I would suggest probably through TRA/ IEA.
Once the assessment is done and it is +ve you go ahead and apply for the PR which is a comprehensive process that assesses the application based on age, work experience (the govt checks at all your work locations).
Your best bet is to hook up with a migration agent who is IN Australia because many in India would have lapsed information often.
The process can take upto a year but is dependent on cases.
U can try www.seek.com.au, www.careerone.com.au.

You research all the companies you might be interested in, and start sending resumes out----alot of them.
firgure out what city you'd like to live in and then search the local newspapers. you'll also need a work visa if you're not a citizen of the country.
Apart from the good advice that others have provided I think you need to check the Department of Immigration's site for information relating to Profession and other skilled workers http://www.immigration.gov.au/immigratio... Employers can sponsor workers but you will need to ensure that all the relevant criteria is met.