VisorCentral.com (http://discussion.visorcentral.com/vcforum/index.php)
- Visor & Deluxe (http://discussion.visorcentral.com/vcforum/forumdisplay.php?forumid=1)
-- Less speculation, more info (http://discussion.visorcentral.com/vcforum/showthread.php?threadid=119)

There is so much speculation about visor. The Pen Computing review is the most balanced and informative review I've read: http://www.pencomputing.com/palm/Reviews/visor1.html
and the zip file from handspring containing a bunch of PDF files is very useful also: http://216.35.16.11/presskit/Visor_Press_Kit.zip
altho it is hard to find on the site, and has some annoying typos (misplaced decimals, etc.)