To send emails to the team members of a project, select "Project management" from main menu and click on the project name.
From the window that will appear, by clicking on the name of the project member from the right hand side "Project team" panel, a pop up window will open with the address of the selected user.
To send an email to several team members, select "Team members" from the left hand side menu. All the users enrolled in such project will be listed:
Select the users and click on the "Send email" link at the bottom of the page. An email form will open up with the addresses of the selected users.