Google Webmaster Tools

I would highly recommend this service to anyone not currently using it. It gives you an insight in to how google sees your site. You can get information like which pages google has indexed, what keywords you are coming up for, you can submit sitemaps and robots.txt as well as lots of other information on your site.

The more you know about how people use your site the easier marketing becomes.

I use blogger, how I build and submit sitemap?

Blogger it's owned by Google,and I don't know if you really need a sitemap. On the other hand, you can always make a blog on your own server and use GSite Crawler to make a good and fast xml sitemap.

Webmaster tools are really good, but this new (2 months) design looks a little bit strange.. may be I have a habbit of old one.

If you wanna know what google thinks about your site then look at google webmaster tools as it will show you what it sees as your main keywords and anchor texts which I use to fine tune my site about. It also has piles of other good stuff to use!

Right, google webmaster tools has helped me so much. But, they are still lag behind on backlinks collecting.

yes
I also think that