Gmane 
Archives mainly mailing-lists related to open source software and allows read and post access to these lists via a newsreader. A web gateway as well as a weblog-like interface are also available. Free service.
http://www.gmane.org/Newsgroup Hosting
Service offered for a monthly fee. Mailing list and web gateways as well as a weblog-like interface are available.
http://www.newsgrouphosting.com/
Talkto.net
Newsgroup hosting provider based in Switzerland. Monthly and yearly renewable plans.
http://www.talkto.net/
Epi Internet Direct: NNTP Hosting Services
Description of the service offered for a monthly fee. Mentioned currency is Canadian dollars.
http://www.epidirect.ca/DiscussionForums/Newsgroups/SFees.htm
Zeppole Services: Private Newsgroup Hosting
Description of the service provided for an annual fee. Free 30 day trial available.
http://www.zeppole.com/News_Hosting/news_hosting_index.htm
Argos Networks: Hosting Plans
Private newsgroups are available as one element amongst several hosting services. Customers can build their own pack from a combination of these options.
http://www.argos.net/Services/Hosting.shtm
Net Atlantic: Discussion Group Hosting
Presentation of this company's mailing-list service, which may also be accessed through a web browser and a NNTP compatible news reader. Free trial available.
http://www.netatlantic.com/products/discussion-group-hosting/
Dundee Internet Services
Mailing-list hosting using Lyris. Specializes in very large, high volume, commercial lists. Private newsgroup hosting also available.
http://mailing-list-services.com/services/
