Apple has released iTunes 10.0.1. You can obtain it via the Software Updates component of Mac OS X’s Systems Preferences app.
The update adds a Ping sidebar in which you can “Like” or “Post” about music from your iTunes library. Plus, you can see the recent Ping activity of a selected artist in your library, or of all artists and friends you follow on Ping. iTunes 10.0.1 also fixes several bugs; namely it:
° Addresses an issue where the picture quality of a video changes depending on whether the on-screen controls are visible;
° Resolves an issue where iTunes may unexpectedly quit while interacting with album artwork viewed in a separate window;
° Fixes a problem that affects the performance of some third-party visualizers;
° Addresses an issue where the iTunes library and playlists appear empty;
° Resolves an issue that created an incompatibility with some third-party shared libraries.