They have links to a bazillion shareware and freeware programs for all platforms. Demos of commercial products, too.
Good place to look first when you need audio software.
Oh, and if you go to the bookstore, "Computer Music" magazine is giving away a full audio suite and this month they're giving away a 48-track/unlimited-MIDI version of SamplitudeSE. For FREE (OK, so it's $14 for the magazine and DVD....)
That's the first time I've looked at hitsquad in years. It's still the same difficult to navigate maze with ads upon ads after ads as it always was back in the day.
If you want a clean (or relatively clean) clearinghouse I recommend KVR. They've updated their search engine so now it's even easier to find free, shareware and commercial virtual instruments.