how does this thing come up.

i mean the sitemap on google.

 

have a read of http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=47334

basically if you have a good directory/subject structure and many inbound links to each section that will help, but only if you show as top result for that search anyway.

 

If ur site has good backlinks and good traffic that will happen automatically in the time frame

 

I'm guessing you would also need to have a very busy site before you get listed like this. Good question, Ive also wondered about this.

 

i do have a lottttt of backlinks and directory submission but not that much traffic.

 

That's not a sitemap.. They are Sitelinks.
If you have a good navigation structure and rank high for long for a keyword, they appears.