Hi Geeta,

The need to learn testing tools is kinda tied up as to what aspect of Testing you want to make your career in.

Incase you want to go in for Automated testing, we have tools like -
1) QTP and WinRunner from Mercury
2) Robot and Ratinal Functional Tester
3) SilkTest and TestPartner.
4) Segue, QARun etc.

These are focussed on functional Automation testing.

But incase you would be interested in Performance testing, tools like -
1) Mercury LoadRunner
2) VSTS from Microsoft
3) Rational Performance tester.

I suppose there are a few testing institutes that train you on these tools. What I would suggest is you download free trial versions of the same and play around using the help files.. You would learn more in that way.

You could also learn defect Management tools like Quality Center.
Let me know if this helps....
Cheers.....