I'm in sales so drive a lot. And sometimes I cross off @Call NAs while driving. It's easy to cross but difficult to put new ones while drive And of course I forget about them. So some projects stop till the next Weekly Review. My GTD "instruments" are Outlook for WR planning + Palm Treo Windows Mobile for daily usage + Moleskine for meetings capture.
Can you give any ideas on how to "update" Next Actions that couldn't be updated immediatelly for a mobile user like me?