Web based project info sharing

Hi,

couldn't find any better place for this, so...

What web based tools are you using to share changing project information with your customers/subcontractor etc? I don't mean anything like "pdf through email", but serious tools that provide better ways to save and maintain information.

What I'm after is something like free project management tool like ProjectPier, www.projectpier.org. It's just those cool tools are missing the "CAD-integration"...so I would like to be able to annotate the files in the system online. Files can be 3dpdf/pdf/eDrw/what ever you can create with SW. Just want to modify those online (and also give client rights to do the same.

Tool like 3DVia is soooo expensive, that it really can't be used :-(

Markku