The 2nd link from good is showing "Bad Request" error :(

Pratheep

You can indeed submit your sitemap xml file to MSN. You have to do it through Moreover. MSN has some partnership with them and I have used it for my site that was not indexed in MSN for three months and after I submitted the sitempa.xml file via Moreover, suddenly I was in the search results. Get the information here http://w.moreover.com/site/products/ind/pingserver.html

Moreover and MSN have been doing that for years, no?

This is a bit different, I thought?

Here is the Google ping URL that I use nightly successfully:

www.google.com/webmasters/tools/ping?sitemap=

The Bad Request error is because you've not put your xml sitemap url on the end of that url.
Example:

http://www.google.com/webmasters/sitemaps/ping?sitemap=http://www.seroundtable.com/sitemap.xml

If anyone still have "Bad Request" error, try pings with encoded urls. for examle:

http://www.google.com/webmasters/sitemaps/ping?sitemap=http%3A%2F%2Fdomain.com/sitemap.xml

I use the following code:
my $url = 'http://www.google.com/webmasters/sitemaps/ping?sitemap=http%3A%2F%2F'.$ENV{SERVER_NAME}.'%2Fsitemap.xml';
unless (defined ($ping = get $url)) {
die 'could not get '.$url;
}