Web resources in .Net 2.0, allow control developers to package up client files such as scripts, images, style sheets etc. and use them in the generated rendering simply by embedding them into the assembly, rather than having to scatter them into the file system.
These are the steps to be followed to generate the WebResource Assembly.

1. create a folder say MyResource in VS.Net 2005 the project
2. Put the recources like .js, .css .gif etc in the folder.
3. Select All Resources and set the Property Build Action to "Embedded Resource"
4. Put the following attributes in Assemblyinfo.cs:-

 [assembly: System.Web.UI.WebResource("myCss.css", "text/css")]
 [assembly: System.Web.UI.WebResource("myScript.js", "text/javascript", PerformSubstitution = true)]
 [assembly: System.Web.UI.WebResource("MyImage.gif", "image/gif")]

5. Compile the project.

Now this assembly will be the Web Resource assembly, It will contain all the compiled resources.

We can access these resources by refering the above assembly:-

.js:    Page.ClientScript.GetWebResourceUrl(this.GetType(), "myScript.js"));
.css:  Page.ClientScript.GetWebResourceUrl(this.GetType(), "myCss.css")
.gif:   Page.ClientScript.GetWebResourceUrl(this.GetType(), "myImage.js"));