When I create new .aspx file and programming it, the .vbproj file is auto check out and the other people can't use this project.
How can I program and not check out the .vbproj so that other people can edit the other file in the same time?
I'm not sure it would be a good idea to no have the vbproj file checked out when you're adding new code files. The .vbproj file needs to be checked out so your instance of Visual Studio can add data about the file you've just added into the project.
You should manually check the project file back in after you've added an item to it so that other users can ensure they have the latest version of the project.
The Visual Studio source control check in dialog is granular enough to allow you to just check in the vbproj file.