If you are a MSDN Subscriber, you can download it from here. However, before installing beta2, you need to uninstall all pre-beta products of VS.NET 2005. It needs to be removed in certain sequence, for more details refer this link.
http://lab.msdn.microsoft.com/vs2005/uninstall/
If you dont follow this uninstalling instructions, you might get into lots of problems in installing beta2.
If you are not a MSDN subscriber, then either you can order for beta2 or you can download express versions of VS.NET 2005
Go-live license for VS.NET 2005 is available for beta2, if you planning to deploy beta2 products in production environment, then sign up for go-live,
http://lab.msdn.microsoft.com/vs2005/golive/
Note: Go-live license is not available for TFS Foundation server.
For more details about beta2 release, refer these links
http://lab.msdn.microsoft.com/vs2005/get/
http://blogs.msdn.com/danielfe/archive/2005/04/17/409073.aspx
http://blogs.msdn.com/bgold/archive/2005/04/17/409045.aspx
Sad part for me is, I have installed pre-release beta2 in my machine last week only... i have to uninstall it and install beta2 again... I will post about my experience in installing beta2 soon..