Thanks all for your advise.
I also have a mac and just assumed that these companies would be making software for both mac and PC. You have given me something more to think about
I also have an iMac and have found that software from people that you'd assume cover Macs isn't always available. I've got a handheld Magellan Triton 400 that I primarily use for mountain biking that's PC only.
A solution of course is to use Bootcamp, buy Windows and run Windows on your Mac. I do that because of a couple of Windows specific programs that I use which work perfectly on my Mac.
Only downside of course is the cost of another Operating platform and boot time switching between OS-X and Windows which seems to take an eternity (reality about 3 minutes.....but you know what I mean)
Off topic......I bought a nifty little 'Camera flotation strap' for my Point 'n Shoot*, which is basically just a padded wrist strap for anyone concerned about their camera going to a watery grave. $20 at my local Camera House.
*The Point 'n Shoot being a Sony TX5 same as Mrs Mitch's which I bought the other day after seeing the excellent results here. (Curse you Mrs Mitch !