Vanilla is obtained from the cured, unripe fruit of Vanilla planifolia which is found in Mexico, the West Indies, Reunion, Mauritius and Seychelles.  Vanilla is 2 - 2.75 % vanillin, about 4 % resin, vanillic acid and about 10 % sugar.  It is used in the manufacturing of confectionery and in various bake goods.  Vanilla is also used in perfumes and in the flavoring of beverages, as well as a pharmaceutic aid (as a flavoring).

Vanillic acid:  4-hydroxy-3-methoxybenzoic acid.  C₈H₈O₄, MW = 168.14.  White, odorless needles which melt at 210^o.
 
 
 

Vanillin: 4-hydroxy-3-methoxybenzaldehyde.  C₈H₈O₃, MW = 152.14.  White or very slightly yellow needles, with a pleasant aroma of vanilla.  Used as a flavoring agent.
 
 
 
 
 

References:
Merck Index, Tenth Edition
Vanilla Bean photo from http://www.sdahldtp.com/vanilla3.htm#topv3
A brief history of vanilla can be found at http://wwwchem.uwimona.edu.jm:1104/lectures/vanilla.html
Also check out: http://www.maneva-export.com/vanilla.htm