If you want to find and copy files with some characteristics to a tar file. Do this:
tar cvf videos.tar $(find 027_Imagenes_Feb09/ -name '*.mpg' -print)
In this case the path is preserved...is very useful.
The complete reference is:
http://www.askdavetaylor.com/how_do_i_selectively_copy_files_from_a_directory_structure.html