The main registrant for each transaction will show on the Summary version of the main Events grid. Select the event to view from the side bar under Events. If you wish to see all the attendees (or guests) for an Event instead of the constituent who registered, you can switch to the Detail version of the grid by clicking the "Switch to Detail" text link which appears next to the "Actions" menu.
All the registrants and attendees for an Event will also appear on the Event Attendance grid. Registrants will be listed under the Last Name/Constituents column and attendees will be listed under the Actual Attendee columns.