You're on the right track. You'll have to append some sort of unique token to each file upload per user... so say user1 uploads foobar.pdf and user2 uploads foobar.pdf... you can do a couple things.
When they upload you can append their user id (since they will be unique) to the file name so it would be 1_foobar.pdf or 2_foobar.pdf.
The other option would be to give each user a folder that it gets uploaded to, again... you'd prolly want to create the folder based off the users id or the users name.
folder user 1
folder user 2
then for your sql insert just have a files table or something like that, has
file_id, user_id, file_name
file id auto increments
user id is the id of the person who uploaded it
and file name is simply just the file they uploaded
Let us live so that when we come to die even the undertaker will be sorry. - Mark Twain
Don't PM me your CSS, xHTML, JS or PHP questions. I will not reply to ANY IE6 questions.