There are two new tutorials now available on the (also new) wiki at this site, both entitled "From Method To Plugin" and describing how to get your code compiled and running as a Vamp plugin. One tutorial covers OS/X, the other Windows.
I hope these are helpful! If you find any errors, please let me know (or create an account on the wiki and correct them!)
The wiki homepage is at
http://vamp-plugins.org/wiki/, and we'd welcome any contributions that might be interesting to other users or developers of plugins.
Chris