This forum has cost me a fortune!
I have the
Nike + attachment for my iPod and running shoes. It's very good at what it does i.e. logging your runs, keeping you informed and praising you when you've finished. (Lance Armstrong and Paula Radcliffe tell you if you've beaten your PB for the distance.) You can log and compare your runs on the Nike + website. However, it's nothing to do with GPS or cycling though (apart from Lance's voice!). Unless, of course, there is a way of strapping your running shoe to to your wheel. That may make the ride a bit bumpy though :-)
Actually I have passed my Nike + on to my son as I got myself a Forerunner 305 for running (and then an Edge 305 for the bike :-) )
Being a sad git - I've reached that age - I also have a mobile phone GPS enabled with an internet data plan on 3 (Three). I use Mobile GMaps which is a free Java app. This can display my postion on a map/satellite photograpy in real time and send my position back so I can be tracked on a website map on the internet (if I so choose). It's a bit flaky though and needs restarting every so often. Keeps the kids entertained though :-) 'Ooh look - Dad's going 10 miles an hour, 30 miles away, still lots of time to wind Mummy up before he get home..'
Also, I have an old Geko 301 which is my favourite for navigating me around. I leave my Edge 305 to do the data for me i.e. heart, cadence, altitude, sweat rate, internet shopping, etc. With the Geko, I upload my route via Memory Map and it gets around there no fuss.