See below. There are many others – paid and unpaid – feel free to add to the list. This was mostly on the freebie release engines.

Press release distribution engines.

www.businesswire.com

www.marketwire.com

http://theopenpress.com/ (Free)

http://www.prweb.com (Paid).

888PressReseases

Pitchengine.com.

http://www.pr.com

www.prurgent.com

www.newswiretoday

www.exactrelease.com
www.freepressbox.com
www.freepressrelease.com.au
www.freepressrelease.com
www.freepressreleasecenter.com
www.freepressreleases.com
www.ideamarketers.com
www.justprnews.com

www.pressreleasepoint.com. (pd nominal)

ereleases.com. (paid at $325)