The IMCE module (http://drupal.org/project/imce) allows you to upload files (either to once central location or separate directories per user) and then browse the server for existing files and attach them to other nodes.

Steve

Davide Michel 'ZioBudda' Morelli wrote: 
Hello everyone,

For a customer I need to use a module to do this:

- Allows me to save a file in the website (/files/)
- Colleagues at the node/ add to get to attach a file previously 
included within this node

I could use the "nodereference" module, but I need the opportunity to 
view a preview of the file that will be choose.. Nodereference puts 
everything in a "select list" and with this method the user is unable to 
handle 20+ "possible" file. And it (nodereference) can not do a 
'preview' of the file.

Someone could do something of this kind can tell or some alternative way

Thank you.

PS: Sorry for my bad english.