I sure don’t, but Louisedade always said his Upload Avatar plugin was originally a file upload script he hacked to use avatars. It might be a good place to start.
Biggest problem you’ll have IMO is where to store post metadata. Usually I hate a plugin to add a table, but in this case it’s probably totally appropriate (and hey, if it works well maybe more plugins’ll use it and/or it’ll be taken into the core?).
I’m surprised nobody has written a plugin for this by now… seems to be a fairly important feature for a forum.
I can probably hack that plugin, was just hoping somebody else had already hacked one together and was willing to share.
hum such a good news some one finnaly wants to do what i want 
This is something I’m looking for as well…
It works!
Going to spend some time playing with it, will reply with more feedback.
I have an interesting idea for this plugin: Make the allowed filetypes be set per group.
That way you can say that regular participants can only upload image files (fairly safe), but moderators can upload documents, and administrators can upload anything (like executables)… it could be easily customized.
HowToGeek, that’s easily doable, just more settings to fill out 
That reminds me that I’ll have to give a list of accepted file types and sizes above or below the upload form.
I’ve now implemented flexible restrictions in 0.0.6 based on file type or role based on your suggestion HowToGeek.
