I have a form/php script I use for clients to send me large files or those that they can't get "out of their system". It's a xara file with a small php upload script in an iframe. It's simple. It lacks a progress meter while the upload is happening, so it just sits there looking like it's hung until complete, then sends to a "thank you" page. For small files, this is a non-issue, as they upload so fast, no one cares, but for large files, it can be offputting,

For large files, you will likely need to adjust the php variables in your php.ini file for your hosting account if you hosting company allows this. You will otherwise be stuck with (I think) 2mb / file limit. Some hosts also impose an invisible limit as well regardless of the php.ini limit stated. dot5 hosting only allows like 30mb per php upload or something. For most, this wouldn't be an issue.

If you are interested in what I have, let me know and I'll PM you some info about the current site so you can see it in action (don't want to post that here since it points right at my server).