Hi,
You have a few options if you want broadband internet without a phone line and each option has its own pros and cons.

Option1- Naked DSL - very few companies are offering this service & the main problem is that although they say No need for a phone line, yet the plans are priced in a way that you actually pay an extra $10 or so per month when compared to the normal ADSL pricing. Although it is still cheaper because with ADSL you still need to add the cost of the phone line on top. I would rather pay an extra few dollars so that I have the option of using a landline when required.

Option 2- Cable broadband-This is another good technology but the problem is very limited availability. Also as more users in your area connect to the Internet your connection will slow down as everyone is sharing the same neighbourhood cable.

My personal favourite is Option 3 -3G Wireless mobile broadband
This option has become really popular this year because all the mobile phone companies have started building infrastructure to increase the speed of their mobile networks & this has helped them introduce TRUE wireless broadband to the Australian market. The technology behind this vast improvement in the 3G network is called HSDPA.

One of the main reasons I have been impressed with this technology is that it is truly mobile & you can essentially take your laptop and work while you are in the shopping centre, in a cafe, at the beach, at a client's office or even while on the train/bus. Basically you can take your Internet connection anywhere.

Three cheers and a beer for Wireless Internet