The applicationn, now at version 2.1, is based on ASP.NET and SQL Server, and is available as a free download. Licensing is free for non-profits or for up to 5 business users. A hosted version is available starting at $40/month for up to 5 users.
Users are encourage to upload their applications to the Iceberg site, either for free re-use or for sale.
The Read/Write web article points to their first look at the beta, in July 2007, and identifies similarities to and differences from Coghead, Salesforce AppExchange and BungeeConnect. Another alternative which I have come across previously is PAT from British company Ninth Wave.
Over the next few days I’m going to try building a simple application using Iceberg and will post my findings here.