Hi Vijay,
As Vinay explains those links will give you enough of information you would be interested to know about type of certification . Now, coming to your another question: " how much is important for career ascpects?"
This is definitely an important thing, whenever you appear for any interview most of the employer would ask you if you have any certification apart from the college degree that you have. The reason is, certfication like MCTS (formerly MCP), or MCSE or MCITP are taken by the Microsoft, or OCP or OCA by Oracle and RHCE, these are the company who have designed the product and they themselves are taking exams so its their authority and that is why it will add more value and weight to your CV when you have them.
Apart from this, from employer's view it will act as a proof of your caliber, but, this is not limited to certificate, experience also count and sometimes (rarely) one may not have much experience but has superb technical know-how and could win.
So, what I will conclude is that it is one's own choice to be certified, it will surely helps to boost your career.
Regards