when i went to the update center, there was an option to manually select the version to update. since the auto required a download of a detectpkg.exe, i figured why or why not. when i manually selected NIS 2010, i was greeted with a splash screen that my current product is already up to date. GREAT!
i took the auto route and the detective directed me to the download screen where i had to download the download manager to download the intended download. microsoft did the same thing for service pack 2 for vista. fortunately, this part of the process, the downloads, took less than 15 minutes. after the download completed, a new screen "appeared" hidden beneath my browser window.
after going off-line and closing non-essential programs, i installed 2010 on top of the 2009, and rebooted. here's where mijcar's recommended patience really frayed. during the verbose bootup after the drivers were installed, the pc sat silent for several minutes. thinking the pc hung, i rebooted. i waited a little longer the second time and the pc rebooted on its own after the drivers installed and sat silently. third time was the charm when i waited and waited, hoping i didn't have to go into safe mode and system restore. eventually, the pc booted up and NIS came out swinging trying to activate.
the configuration settings changed its groupings from 2009 to 2010. and the 'program control' settings from the previous install were gone, which means i'll have to visit this portion often for the next few weeks to stay on top of "new" program additions.
<<edit: subject edited for clarity>>