Taking on the responsibility of having a companion parrot in your home is a very serious decision. Weigh it heavily, and consider the reality of living the rest of your life with an intelligent, sentient being roughly equivalent to a two-through-five-year-old child in a little feathered body for the rest of your life.
A parrot can be highly rewarding if you really commit yourself and approach the bird with the right attitude. Parrots require a lot of space in your home, hours of daily interaction time, and they can be expensive.
I wholly agree that one must do the research before making the commitment to buy a parrot.
This is where I started my research before bringing home my Congo African Grey:
Sally Blanchard's Companion Parrot Handbook
It can be found at:
It is kind of expensive, but you may be able to find it cheaper elsewhere (like maybe Amazon.com).
I'm not trying to discourage you, but there are too many parrots who are bought with high expectations, and then neglected when their owners lose interest. It is very sad, because these birds are highly intelligent and sensitive creatures.
I believe that your inquiry here is proof that you are pretty serious about doing the best that you can for the bird that you might get. Good luck!