I have just tested to deploy sandboxed Web Part on Office 365 and it’s working great !

Here is a quick summary on how to do that:

1. Create a sandbox Web Part in Visual Studio 2010

(Note the SandBox is true otherwise deployment cannot be done)

2. If you try to deploy directly from VS you get the following error :

3. Instead of doing this, just upload the solution to the solution gallery on your Office 365 Portal:

Note that the default quota is 300.

4. Activate the WebPart :

5. And then just add the Web Part on the page !

These are really great possibilities for this Office 365 and SharePoint…..