Hi gowtham sundaar,
I found a way to post a applet to a blog from blospot. I was also searching for a solution and found one.
I developed my applet using Netbeans
IDE and when I built it, netbeans generated 4 files: a html, a jar, a txt and a jnpl.
My main problem was also where to upload the files, and after doing some research on the internet I found that it is possible to post files to google sites creating a new site associated to your Google account, and a page for holding files. After that just upload the jar and the jnpl files. Then edit the the html file, changing the url for the jar and the jnpl files and ponting them to the google site upoloaded files urls. Run the html file on your dektop and see if it works. After that copy the content from the html file to your blog and post it.
Take a look to my Roman to Numeral applet at:
http://3hconsulting.blogspot.com/2010/11/creating-applet-for-roman-to-numeral.html
If you have any doubt or question please fell free to contact. I will update the content of my blog post adding some more details.
Hetul