Umbraco/Plugins And Extensions/Upload Progress
Upload progress bar 
An Umbraco plugin that allows you to display a progress bar when uploading a file. This is likely to be integrated into Umbraco 3.0.
The plugin can be downloaded from http://www.darren-ferguson.com/code-bank.aspx
Install instructions are contained in the zip download.
Please mail me at df at darren hyphen ferguson dot com if you encounter any bugs or issues.