I have two devices I use for follow up. My iPhone which has a calendar with alarm and also my Palm has a good calendar and alam as well. Either one will do the job, but I beleive in redundancy and use both. That way if I am busy and only get the info in one unit I have it when I need it. The hardest thing to learn is to put the info in as soon as possible.
When I have a deal in Escrow I use an xl sheet to track important dates for contingency dead lines. Then put the dates in my Palm and iPhone with alarms set to remind me 24 hours in advance of an important date. - Wed Jul 7, 2010