This WordPress plug-in removes that annoying install dashboard adware nag that makes you want to stab the developers at WPMU in the eye with a brick everytime you install one of their plugins. (Just my opinion.) This has been tested and works with most all of the plugins they offered as of October 2012.
They’ve been getting wise to this type of circumvention of their dashboard by obscuring the code that calls the nag dialog box, so your mileage may vary depending on the lasted updates. I’ll try and keep this updated.