Check out the IMCE module (http://drupal.org/project/imce).  It allows you to specify unique user directories for file uploads.

Steve

Daniel Carrera wrote:
Hello,

In Drupal 5.9 what happens if two users upload files with the same name? 
I'm concerned that the second upload might overwrite the first. In my 
site there is a pretty good chance of this sort of thing happening. In 
my ideal world the file upload module would use sub-directories for each 
user, but it doesn't.

If anyone can recommend a good module for file uploads, please let me know.

Thanks.
Daniel.