Okay, here is it... it's little app but can be usefully for someone.

Is written in VB.NET 2.0 and using XML file as storage of posts.
Without administration or managing, deleting or editing can be do only manually editing xml file.
Anti-bot as CAPTCHA code verification is included.

Working example can be found here: http://area-71.net/nanoXML/
and sources is here: nanoXML.zip (10.69 kb)