The Video Game Library - a fantastic database of books about games (link is to the Shareware Heroes entry)
Atari Legend - reviews and interviews about old Atari ST games, many of them shareware or PD
The Ultimate Oldschool PC Font Pack - the source for the fonts used on this website, complete with detailed and exhaustive information on what fonts were built into what systems and OSs
[anything else I should link to?]
Further playing
DOSGames.com - Loads of old DOS games to download, with a brief review, star rating, and video attached to each; includes filters for shareware and freeware titles
Macintosh Garden - The definitive collection of old Mac software, with a great community of vintage Mac lovers
Atari Mania - A huge database of software/games for various Atari systems; link goes direct to the list of all PD & shareware Atari ST software
Lemon Amiga - One of a few excellent databases of Amiga games; link goes direct to the list of all non-commercial (including shareware) softwre and games they have
Further watching
FPS: First Person Shooter - A 3+ hour documentary I'm working on as producer and co-writer (fellow author David L. Craddock is co-writer/co-director)
Matt Chat - Matt Barton's excellent video interview series, where he talks to game devs and authors like me in depth about the history of video/computer games
Pixelmusement - More videos about old PC games, with a special series dedicated specifically to the stuff that would get put on shareware compilation CDs
Play Different - Videos about old Mac games, HyperCard stacks, and multimedia software, with a particular focus on obscure and community works
[let me know if you think something else should be here]