Code project is a great site it focuses a lot on C# but is great for .NET in general, in many cases there is code you can use in your own projects as well.
My favorite Linux distribution, such a great distro that other popular distros are built on it, including Ubuntu and its derivatives, Untangle the Internet gateway, and the gparted Live CD. It is easy to install, has an unbelievable number of packages available from default repositories and the stable version is rock solid. Its apt-get system for package installation has been copied by other RPM distros.
Great software for small Systems/Network admins dealing with Windows or primarily windows networks. Assists you in tracking equipment, has a full featured Help Desk for your use, can send of alerts to email addresses for alarms you set up, and is just a life saver. There is also a great community that supports other users. Requires XP or better OS to run.
This is the download page for XEN 4.0.0 download. This seems to have some bugs in it, you might want to try testing if this doesn't work for you. Or try 4.0.1 when it becomes stable.