1. Yes. USB or pc card mobile modem.
2. You need mobile broadband, which is not the same as wireless networking. Find out all about it on the Bigpond site. If you have an ABN, it is much cheaper (but still not cheap). In this case you must organize it via the telstra.com site.
Chris B

Hi Bob,
You ask two questions:
1) Do you need any extra hardware.
Answer is no, you do not need any more hardware. Usually this connection will be done through the connection made available either in a hotel or any available hot spot. If you are in a hotel, simply go the desk and tell that you want internet access and they will give you a passkey that will need to use once your computer finds the SSID (hotel network connection) The desk will give you this information. Hot spots are similar. Simply tell your computer to connect and it will find all SSID's in your area. Simply navigate to the one given to you by the hotel desk, and use the passkey that they will have given you.
2) Setting it up so the your have normal cable at home and wireless on 'rout'. Simple. Your cable connections is always available in the laptop - don't need to ever change that to do what you are asking. When on 'tour' simply ignore the cable connection and connect to wireless as explained above.
Note of caution you would be wise to use a secure tunnel to protect your own data while on these 'public' or 'private' networks, as you will have no idea who is spying into your computer. Suggest you use: Netstumbler (http://www.netstumbler.com/) & ipig (http://www.iopus.com/ipig/). You might also consider this download from microsoft if you think you need it - This is for wpa2, which has support for AES (Advanced Encryption Standard). Download from microsoft: http://support.microsoft.com/?id=893357

Bob,
Your onboard wireless should connect to most hotel, McDonald, hotspots etc. Depending on where you are trying to connect, you may have to set up an account with the user, some hotels and airports offer free internet.
As for setting up, all you need to do is ensure that your wireless is enabled and it should work fine as you don't have a modem plugged into the ethernet/usb port. If you want to ensure that it selects the cable internet back at home, just disable the wireless on your return. If you are not sure, most laptops have either a switch or function key that will turn wireless on and off or fialing that it is a right-click mouse option in network connections.
Cheers
Matt

Thanks to all who replied - I will give it a go when I next go away from home for a few days. (It doesn't appear to be that difficult after all!