Yeah, I've installed a few pieces of software from there, and haven't had any problems. Basically, software companies agree to provide completely legitimate software to the site for 24 hours. It's pretty handy, because lots of people vote on whether they like it, and provide comments about the good and bad aspects (and often offer good alternatives too).

There is also a game giveaway of the day.

I'm not sure if the software is all PC based though...