Just a quick note that we have validated our IntelliGantt Web Part for SharePoint Online in Office 365. The folks at Microsoft we're kind enough to let us work with the beta and, after a couple hops and a skip (but no jumps!) we had the sandbox version up and going.
We could even put the web part into the Project Management category, which we are excited about:
And here it is running within our teamdirection.sharepoint.com site, which is 100% fully SharePoint Online within Office 365.
The really cool thing is you get complete web part editor backpage support so configuring the IntelliGantt Web Part is a snap. And for consultants setting up Office 365 sites for their clients, don't forget about our branding features.