Hi all,
Since I'm new to web technology , can any tell me how to host a site. I have created a small application using asp.net which runs in my local.

Shop for a host and they'll give you space to upload it to. You'll have control over that space (and probably some tools, software, etc. to go with it) just like you do the space on your hard drive.

The host will tell you what nameservers to enter for your domain name.

I like Lunarpages for hosting. Here's info on their basic plan: Basic Web Hosting Service | Lunarpages.com

First you'll need a domain name, godaddy.com offers pretty cheap domain names. Personally I prefer register.com, they're more expensive but if you call them up when you register your domain they will probably match godaddy's price. (I just renewed a domain for 2 years and when I called them they beat godaddys price!)

Then, as RickJ said, you need to find a host to handle this for you. Being a .NET application though you might have to pay a bit more for hosting... it depends on what your application needs. Cheapest Hosting offers .NET hosting starting at $7.95/mo

You can also do this yourself, assuming you have the hardware and software already, it's not overly difficult but it's more involved. Also, depending on the bandwidth requirements of the application, it could degrade your home internet connection.

Most hosts will handle the domain registration for you, so find a host first, check their package, then see if you need to use a separate registrar.

Get hosting from a LOCAL company and stay away from the big $5.99/month hosting offers. They are typically not worth anything.