first make sure that the login user is under the 'Technical Features' group. You may find this setting in Settings-Users-Users-YourName-Access Right.

Once you set 'Technical Features' Access right for the current login user, refresh OpenERP page and you will now see the below mentioned menu items.

1) visit Setting-Automatic Actions-Automatic Actions, refer to the existing auto action settings, you will know how to create an auto-action to assign a sales agent and/or a sales team for the incoming leads and/or forward the email to particular user email or a group of emails.

2)Normally we will record sales activity on opportunities, you may convert the leads to an opportunity. In the Opportunity Kanban or Form view you will see the send email button.

Hope it is useful.