24-7PressRelease.com – Free release distribution with ad-support
1888PressRelease.com – Free distribution, paid services gives you better placement and permanent archiving.
ClickPress.com – Distributs to sites like Google News and Topix.net, Gold level will also get you to sites like LexisNexis.
Express-Press-Release.com – Free distribution company with offices in 12 states.
Free-Press-Release.com – Easy press release distribution for free, more features for paid accounts.
Free-Press-Release-Center.info – Distributes your release, offers a web page with one keyword link to your site. Pro upgrade will give you three links, permanent archiving and more.
I-Newswire.com – Allows for free distribution to sites and search engines, premium membership differs only slightly in adding in graphics.
NewswireToday.com – All the usual free distribution tools, premium service includes logo, product picture and more.
PR.com – Not only will they distribute your press releases, but you can also set up a full company profile.
PR9.net – Ad supported press distribution site.
PR-Inside.com – European-based free press release distribution site.
PRBuzz.com – Completely free distribution to search engines, news sites, and blogs.
PRCompass.com – Distribute your press release with a free or paid version, others can vote it up ala Digg style.
PRUrgent.com – Not only distributes your release, but attempts to teach you how to write one, and even offers downloadbale samples for you to work with.
Press-Base.com – Submit your release for free and get on their front page and the category of your choice.
PressAbout.com – A free press release service formatted as a blog.
PRLeap.com – Free distribution to search engines, newswires, and RSS feeds. Fee based bumps get you better placement.
PRLog.org – Free distribution to Google News and other other search engines.
TheOpenPress.com – Gives free distribution for plain formatted releases, fees for HTML-coded releases.