What GPS?

If your laptop has Bluetooth the Globalsat BT338 works pretty well. I bought one off Ebay at a pretty good price. If you are talking a mapping program, a lot of people use Oziexplorer for outback touring. You have to get the maps separately though.
I use my NextG LG TU500 phone as a modem and have purchased a data pack.

recently purchased a Garmin eTrek Legend Hcx colour with basic maps. Loaded the freeware Shonky Maps. 24hr battery life, basic maps and 10,000 track points. When not connected to the laptop still records your tracks. Can be used in its own right to go places. Small enough to take walking and cycling. Paid $425 and happy with choice.

recently purchased a Garmin eTrek Legend Hcx colour with basic maps. Loaded the freeware Shonky Maps. 24hr battery life, basic maps and 10,000 track points. When not connected to the laptop still records your tracks. Can be used in its own right to go places. Small enough to take walking and cycling. Paid $425 and happy with choice.

I have a programme fom these guys ..it is magic.
Auto tracking.. just set it before you hit the track and it automatically tracks where you've been and you can always see where you are. easy to mark present position and add pics if ypou want. Trip planning is a breeze, working out mileage ahead etc.
All you need to start with is a laptop. have alook at their site. Great guys to deal with too, had a few issues geting started, they talked me through it and I was up and running within an hour.
Maps all over Oz and all City maps too.

http://www.advantechdesign.com.au/trackranger-gps