To make a short story long...
about a quarter of the sites on these lists had gone out of business. Several turned out NOT to be free - and I found this out after going through the time consuming and tedious process of applying to be a member, writing about my company, filling in the press release information...
and several of them apparently got swallowed by my spam filter on my email account so I applied to submit a press release and never got an email with a confirmation link...and one of them I filled out the form several times and finally got accepted, submitted the press release, and it told me that there were MySQL issues and I couldn't submit it...and one of them I filled out the application form and it turns out I can only submit stuff for myself, not for clients, which does me no good...
So, to save you all of this misery, here is my list of free press release sites which as of yesterday were still up and running, and to which I successfully submitted press releases: (And if you have any that are NOT on this list, which you use, please let me know!)
Press Release Distribution & Free Press Release Submit @ 1888 PressRelease.com
Free Press Release Distribution Center - I-Newswire.com
Express Press Release Distribution (Free)