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