1.So From where i can start learning .net and complete this project.
is there an sites/tutorials which u know :?
Try out this site. I am sure this will help you to start off with: http://howtostartprogramming.com/vb-net/

2.what is differ b/w asp.net or vb.net. I think we r doing it in asp (may be a foolish question).
ASP.NET is used for web applications on a web server. However using VB.NET, you can code for Windows Platform

3.Which application(windows) should i download for writing source code ?

OR

Should i go for a course and study the project instead of above mentioned questions ?
I would suggest to study the project before. You should try out basics before and directly shouldn't dont jump to the sourcy

BTW i would suggest you to start with c# then VB.NET. The end result is pretty much same and one could be converted to another but syntax of c# will help in learning other web languages