I build a little application in vb.net to enhance my course. Now, I want to add to my application a new feature, which allows me to automatically publish the content. Is there any api, which I can use for this purpose?

Hopefully you worked this out yourself but in general a more specific question helps.
Publish can be several things ranging from simply printing to generating a SCORM or stand alone module even publishing and posting it to a web site. They're all a lot different.
Of course once you've added something, VB net is a different technology to java, all bets are off as to how you do anything at all.
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It does spring to mind that if you've made an application that enhances the module and interacts with it then you will already have exposed the SCORM API and hopefully be pretty familiar with things like how xml is used to generate web pages.