Self Hosted Dropbox Alternative?

Does anyone know of any self-hosted Dropbox alternatives?

We have a need to share files/folders between staff and partners (small scale) and for various reasons we'd prefer to host it ourselves.

Sharepoint seems a little too focussed on "check in/check out" and things like webdav/ftp seem a little kludgy.

In an ideal world something where you (as an IT person) can setup an area, make a user "owner" and from there they can add their customers would be great.

Windows or Virtual Appliance would be ideal.

Thanks.

From serverfault Hutch

• The people behind MyNetworkFolders offer such solutions for those who prefer something self-hosted.

  From adamo

• Zendto

  "This is a web-based package that will let you provide a secure and easy-to-use method for your users to be able to exchange files with other people, even with people on other sites that do not have any login rights at your site. Unlike other commercial services, you do not have to trust your files or login rights to any other services; you run all of it yourself. It integrates with your existing authentication system if you have one, or else it can use its own secure SQL-based user authentication system. It will integrate with any Active Directory, LDAP or IMAP system you already have in place. It was originally based on the "Dropbox" package written by the University of Delaware."

  From Linker3000

• http://www.sparkleshare.org/

  I haven't tried it though.

  From Lamnk