Hi Smitha,
The RUP is certainly used and will be used in future. Moreover the agile's iterative development is based on RUP since RUP also encourages iterative and incremental development. I strongly belive that Agile and RUP goes hand in hand good methodologies. However Agile puts more emphasis on 'construction' phase of the project by defining product backlog, iteration backlog and
unit testing etc. RUP is more process oriented and has phases starting from inception, eloboration, construction and transition.
You can do RUP and Agile certifications, both are good and there are many companies adopting to either RUP or Agile or even to traditional SDLC Waterfall approach.
Sai Surya, SCJP 5.0, SCWCD 5.0, IBM 833 834
http://sai-surya-talk.blogspot.com, I believe in Murphy's law.