First, go to Settings->Accounts & sync and select your Gmail account. Do you see "Sync Calendar" there? If so, then your phone should be syncing with your Google calendar.
Next, go to Calendar, hit Menu->Calendars to display. What calendars do you see? "Phone calendar" is the one that syncs with Outlook. You ought to see your Google calendars listed as well (My Calendar is usually the default Google calendar). If they're unchecked, then you won't see them in your calendar view--make sure the ones you want to see are checked.
Also, if you go to Menu->Settings, you should see your Gmail account listed there. Tapping it will give you a list of your Google calendars, and checkboxes to select which ones you want to keep synced.
Finally, if you go to Menu->Settings->General settings, you can select the default calendar that events you enter on your phone will be saved to. Tap Default calendar, and select the one you want.