What are you using for a receiver? Do you have a TNC?
I am using UI-View32. It's not free, but it is worth the $$
if you are going to use it frequently. Also it's easy to interface
a weather station such as a Davis brand and send out the
WX data over the air on 144.390 mhz.
http://www.ui-view.org/
I have a bunch of maps that I made using Delorme SA6 if
you decide to use UI-View32.
If you have any technical questions, refer to this Yahoo
Group (search is your friend!).
http://groups.yahoo.com/group/ui-view/