Here's an edited transcript of a live chat with CrystalTech support (my Web host) that might help someone who has this problem in the future:
Me: I'm having trouble posting to my WordPress blog at xxx.com. When I click the Publish button, the browser’s status line says “Waiting for xxx.com…”; the cursor turns to an hourglass; and it just stays like that until I click the Stop button on the browser.
If I leave it for about 15 or 20 minutes, the browser (Chrome) throws an error: “The webpage at http://xxx.com/wordpress/wp-admin/post.php might be temporarily down or it may have moved permanently to a new web address. Error 101 (net::ERR_CONNECTION_RESET): Unknown error.”
Can you see anything odd on the Web server that might be causing this?
CT: Looks like our SRX firewall is blocking it. What this does is stops sql injections. I have seen this before with WordPress. I can disable it for your site, and it will stop blocking it. WordPress already has something that protects against sql injection anyways.