Upload files - progress bar


I have a section in a site that alow users to upload big files… like files with 20mb and more. This are updates for a software.

What I want to do is display a progress bar with the progression of the upload file, because that files are big… takes a long time and sometimes users get boring or press ESC or something like this…

Anyone know anything ?? It can be with php, javascript, flash (AS) … something eheh

thks ! :geek: