You should have a calendar app on your Android device. If you're happy with your current calendar, go directly to (1); otherwise, you may also go to Android Market to download and install a calendar app like "aCalendar".
- On your Android device, go to Android Market, download Hotmail app (by Microsoft + SEVEN)* and install it
- Open Hotmail app, setup your Hotmail account
- Press and hold on your account, select Settings. In Calendar item, check "Sync Calendar". Return back to Account Settings
- Press Sync New Calendar
#Hotmail sync also supports other phones like Windows Phone, iPhone, some Nokia phones and BlackBerry phones. - http://explore.live.com/hotmail-mobile?T1=t1
*There are other apps with similar names. However, this is the only official app for Hotmail sync.