Assuming that your web application is running without problems locally, you have to proceed as follows:
1- Find a suitable hosting. The guys did a good job on how to do this.
2- Now that you have a hosting, you have to verify that the hosting plan is enough for your needs. For example, you have to verify if the hosting provides you with MS Sql Server if you're using it locally.
3- Assuming the hosting plan you have has what you need, you need to choose a method of deployment. The easiest and fastest way to deply a .NET web application is to simply copy the application files through FTP (or whatever alternative method). This copy of the application AS IS includes copying markup and source code to the web server. If your application uses a DB, you have to create the DB online.
Another option for deploying a web application is by uploading DLL's. If you do not wish to upload your code to the web, you can use VS to publish your application online through going to Website > Publish
(
http://www.beansoftware.com/ASP.NET-Tutorials/Deploy-ASP.NET.aspx )
http://www.15seconds.com/Issue/030806.htm
http://aspalliance.com/1464_Deploying_ASPNET_Applications.all
http://www.startvbdotnet.com/aspsite/extras/deploy.aspx