The CSIRO Australia Telescope Outreach and Education site has some fantastic tips for holding a viewing night.
Know your telescope!
You need to know what the weather is going to be like.
Weather Zone has excellent satellite images to show you the cloud cover.
The Weather Channel has hour by hour predictions of the weather over the next 48 hours. Although the temperatures are in Farenheit.
The Bureau of Meteorology also has satellite images and a 24 hour animation of the movement of the cloud cover.
Don’t know which star that is?
Free software Stellarium can be installed easily onto your Windows or Mac machine.
There are also a large number of iPad and iPhone Apps which also allow you to identify the objects in the night sky.
Distant Suns 3
are just a few of the cheaper and recommended Apps. Many also use a fantastic Digital Compass where you point your device at the object you are interested in and the app will spin around to show you your view with the labels of the objects.
Astronomy Online has a very comprehensive list of software and apps for all platforms
Want to know what is worth looking at in the sky tonight?
The Melbourne Planetarium at ScienceWorks publishes a monthly newsletter of what is in the night sky as well as news and events.
For a broader view of everything in the Southern sky this year, Southern Sky Watch 2012 is essential
Many of the Software and Apps listed above can show the night sky at any particular night and time.