From what I've read in the Google Webmaster Forums, a mobile xml sitemap is the best fix for this situation. Also, I'd say make sure that regular googlebot gets redirected to the main site like any regular browser would, but googlebot-mobile gets served the mobile page and is not redirected.

Hi pankajj - John Mueller of Google recently did a Q&A session regarding mobile redirects and rankings, and in one answer addresses the issue of mobile pages outranking desktop pages for 3-4 word queries. He suggests the canonical as a possible fix....

Mobile Websites & Google's crawling, indexing and ranking
June 3, 2011
[plus.google.com...] [plus.google.com...]

Sometimes that can happen if the mobile pages are indexed on their own. In general, one solution to that could be to use the rel=canonical on the mobile pages, pointing to the desktop versions. When mobile users access the desktop pages, you could redirect them to the appropriate mobile version.

I just mentioned this Q&A session and another mobile discussion and Google mobile guidelines in this thread here....

Mobile Redirect Header Response and SEO
http://www.webmasterworld.com/google/4363444.htm [webmasterworld.com]

Thanks Tedster and Robert. To what I understood here is of using canonical tag on mobile pages. I reviewed our webmaster settings and mobile sitemaps as well.
Using canonical tag will mean implementing the intelligent codes across the desktop version to re-direct mobile users to wap pages.
Other way maybe in the sitemaps and web pages itself.

Is there a way in the mobile sitemap file, that I can say that these pages are only for mobile version for the searchbot and likewise is there a tag that can be used in every mobile page stating these pages are for mobile users and not desktop.

Am not in favor of canonical to be used here.

Kindly suggest

Is there a way in the mobile sitemap file, that I can say that these pages are only for mobile version for the searchbot

That is the whole point of the Mobile Sitemap format. Google will understand your intentions as long as you use the format they explain here: [google.com...]

and likewise is there a tag that can be used in every mobile page stating these pages are for mobile users and not desktop.

That's up to your website's technology - how you capture information about the user agent asking for the URL and your follow-up logic about whether to redirect the session or not.

By the way, many major sites redirect mobile users when they ask for the desktop URL but not the other may around. There's not much downside from that practice, as far as I can see.