I had submitted my Podcast to itunes 6 months back. Its still now showing up. What could be the reason.. When I try to submit the Rss Fedd it says that the Rss Feed is already submitted.. What shhould i do next ?

The 'already submitted' message means that it recognizes your submission. However it shouldn't take six months. Presumably you've tried searching on your podcast's title. You could try contacting Support: go to https://itunespodcasts.zendesk.com/hc/en-us/requests/new and click the disclosure triangle at the right of the 'Choose a topic' field - choose 'Submission enquiry' and proceed from there.

If you have questions about your own podcast it's best to ask them in the 'Producing Podcasts' forum. You should always post your feed URL when you have a question (and the Store page URL if you have one).