Would you please suggest me how to hire the magento developer as I want to upgrade my existing website in Magento Platform.
What are the tools required for that ? From where I can hire the part time PHP developers.
You can actually try those sites that were suggested above.
Elance and Odesk are good places to hire developers and programmers as they have massive network of people from different locations around the world. Most of the time, these sites used an escrow system in hiring freelancers which makes it more conducive for clients and staff to understand their common needs.
Although you can also try other sites like Staff.com which is perfect for those who are looking to hire FULL TIME and PART TIME freelancers. Other sites don't focus in this aspect (full time hires), but this site does.
The way they hire freelancers is that they will allow you to conduct a 10-hour trial work for the staff so you can fully gauge their skills and how fast they can finish a certain project. If they perform well in the first 10 hours then you can keep going and hire them for a full time or part-time position.
I think that 10-hour trial may be a short depending on what you want to test but definately it can help you to know if they know what they do and, also very important, a glimpse of the attitude they have.
When you see someone that may suit your needs, you should investigate him/her. His portfolio may be great but not necessarily true. Also, the number of starts or good comments that you may find about him in elance or oDesk or whatever place you choose to find your developer may be biased and not reliable (this is not always the case but it can happen)
So searching for that particular person and trying to find more information about him could be good: google, facebook, linkedin... and anything you think of
While hiring a PHP and Magento developer for website these things should be keep in mind.
The developer must have
If a developer have knowledge of all these points then hire him for magento web development.