It is possible with a upload script most written for php, but is limited for upload, due to php.ini limits, which you can extend to larger files, but will stay limited to the time your server allows a script to run.
If you have fast upload 100+MB should be no problem, after changing the php.ini
Also you better trust the uploader not to upload any dangerous files or use a script that has allowed file types options.
This script gives you the option to choose a single directory to upload to and set the file types allowed to be uploaded.
just google it and several download links appear.