Go to Administrative tools -> Local Security Settings -> Local Policies -> Audit Policy, and on the right pane set the events you'd like to have logged in the event viewer.
As for sending an email or message upon login - you can create a batch file that will do that, and add a shortcut to the programs->startup folder. This will cause the batch to run whenever a user logs in (though not when a user connects to a disconnected session). As for sending an email, there are plenty of free command line emailers on the web, just pick one up. Or, you can NET SEND yourself a message.
Lastly, you'd probably get better answers than these on serverfault.com, where more sysadmins would hang out.