When I go into Accounts and Sync, only the primary (first) Gmail account I setup shows an option for Calendar sync. The second Gmail account doesn't even show an option for Calendar. So, it doesn't appear to do it natively.
However, I got it to work when I went online and logged into my second Gmail Calendar account and opened the Calendar Settings/Calendar and clicked on the calendar I wanted to share and added my primary Gmail account as a specific person with permissions to make changes. Then, I did a sync of the primary Gmail account calendar on my phone and the new second account calendar appeared on the list of available calendars. I not only see those events, but because of the permissions, I can make changes which flow back to it. BTW, that second Gmail account calendar is the one I sync my work calendar to using Google Calendar Sync at work. It's nice to be able to view my work calendar events on my phone when I want to simply by selecting it in my calendar. In fact, Android Agenda Widget lets me even place a widget on my homescreen with any mix of calendars I have available on my phone. It makes it nice to have one widget displaying my personal calendars and another widget displaying the work calendar.