The answer as it appeared in 2011
You can modify the AssemblyInfo.cs file. This exists per project. In recent Visual Studio versions it may be nested under "properties" visual studio folder under the project.
Go to your project, expand that, go to "Properties", expand that, open the "AssemblyInfo.cs" file.
Most likely you'll see it end with:
// Version information for an assembly consists of the following four values:
//
// Major Version
// Minor Version
// Build Number
// Revision
//
// You can specify all the values or you can default the Build and Revision Numbers
// by using the '*' as shown below:
// [assembly: AssemblyVersion("1.0.*")]
[assembly: AssemblyVersion("1.0.0.0")]
[assembly: AssemblyFileVersion("1.0.0.0")]
So, you can change the attributes.
Update (February 2011)
Also check: