Gear list/weight application.
I just stumbled across this handy gear list app http://geargrams.com/ It acts basically like a spread sheet you can share. You put in all your items with weights. And it calculates totals. You can also make separate lists for say hiking, backing packing, hunting etc. etc. You can then share the lists with others via url.
No matter what outdoor activity you do you should weigh all of your gear. It will greatly affect your time outdoors.