Forum Hosting 
1. .premodded 
Offers a modified phpBB with a lot of mods installed, so administrators save the time to do it.
http://www.premodded.nl/
Provides free and fully customizable forum message boards for creating a community around a website. Includes exclusive options, smilies, and a lot of features. In English and French.
http://www.aceboard.net/
3. Board Zero
Free phpbb forum hosting service with over 450 styles and 55 languages, no popup ads, instant activation, search engine friendly.
http://www.boardzero.com/
Offers free forum hosting for Invision Powerboard discussion boards. Features instant software set-up. Premium services also available.
http://www.forumhoster.com/
Provides discussion board hosting based on IPS Inc's Invision Power Board. Full admin control and no popup-ads.
http://www.getfreeforum.com/
6. FXBoard.com 
Message boards for Web sites without programming. Free basic account storing 300 messages available.
http://www.fxboard.com/
7. My Guestbook 
Free guestbook hosting service. Also includes a paid option to remove ads.
http://www.myguestbook.co.uk/
8. Nabble
Offers free hosted forums with powerful search to find forums or topics of interest. Currently has thousands of active forums and is growing.
http://www.nabble.com/
LingBring Inc. hosts marketing oriented scripts such as directory lists, forums, calendars, mail forms, guestbooks, refer-a-friend, ask-an-expert for other Web sites.
http://upwithabang.com/