NPO Sodis comes the free Array Importer add-in...
This plugin allows to create many family instances with one click. Coordinates (X,Y,Z) of each instance are taken from text file. The file lines must be written in format:
Necessary is only position block (first), other parameters are optional. I.e. if you want to fill Comments field of instances, you must specify "...;Comments:comment_1;...;.
For each line in file one instance will be created.
There's more information available on the Autodesk Exchange Apps website.