Cnet will not actively add or update software themselves...they leave that entirely up to the individual software authors, if and when they so choose to submit the updates. Thus, I'd suggest e-mailing the author directly and suggesting he/she update the download.com listing. Chances are he/she just forgot.
To anyone affiliated with cnet:
The version of stellarium you offer is quite old:
Please update it so that users who download it from your site will have the latest version 0.9.1 available at www.stellarium.org