We have just put up what should be the first of many new user contributions here at XNAResources! Spark is a game demo in early stages of development... The game is kind of a mix between Geometry Wars and Ikaruga with some gravitational physics! Better yet the source code is available so if you are working on anything that requires some form of physics implementation than you have got to check this out!
Daniel Crenna has posted a free floating camera game component for XNA over at his blog... the full source code is available so if you are looking for a way to get started working with 3D in XNA then this might be just what your looking for! The mouse control vertical and horizontal rotation and the scroll wheel zooms in and out!
Sinnix over at 360Prophecy has just posted some XBOX 360 controller images over at his blog... These buttons look GREAT... they are not just screen caps from another image of the controller... instead they are hand made in Photoshop with that shinny glossy look that is so trendy right now! They have a download with each of the individual buttons in PNG format as well as a .psd so you can make you own buttons or customize theirs! This is a MUST HAVE for anyone working on a game in XNA right now!
Chuck over at gamebasement.net has just posted some information to his blog about creating skyboxes in XNA. Chuck brought us one of the first mesh importers for XNA since the Content Pipeline didn't ship with the beta! There isn't any source code available right now but it's a good read if your struggling with getting things going in 3D. He also has the guts of a scenegraph editor almost ready to be rolled into an XNA Express level editor!