eehm sorry, thank you Viktor. The solution provided by Mehdi, as he said only works on a override position or template variation. We don't need to touch that things only for get a field attrib.
As Viktor well said, with *file_size*, from the same field html typography, will get the file size.
But, if you want to get the value of this field, from another field (I usually get all the values from a single field if they have the same permissions) you must use:
$cck->getFile_size('your_upload_field');
And so, you can load all fields of content on a hidden position, and call all of them with your own html/seblod snippet on a single field, like this:
<a href="/$cck->getValue('some_field');" title="$cck->getValue('other_field'); - $cck->getValue('another_field');">*value*</a>