The collaborator’s toolkit

Notes
Jotspot – Take one set of notes, live. http://www.jotlive.com/

Mind mapping
Mayomi – Mind map & share. http://www.mayomi.com/

Whiteboard
Webbrush – Collaborative drawing, charting, etc. http://www.stanfy.com/dev/webbrush/

email, address book, calendaring, web documents, etc.
Zimbra – Work & communicate together. http://www.zimbra.com
your work organized instantly. really. foldera.com

Wordprocessor
Writely

Spreadsheat
Google

Todo
basecamp

Client feedback
TracBac makes it simple for designers / creators to share, comment, collaborate and interact with their clients. http://www.tracbac.com/admin/

Forum
getvanilla.com

(some day I will finish this)

EDIT: more like, it will be obsolete.