Originally Posted by
txrandom
I just keep track of it in an Excel spreadsheet organized by tabs.
I use these columns, but I could probably extend it by adding reward bonuses, time to cancel, etc: Name, Company, Account Number, Network, Expires,PIN, Phone (US), Phone (International),Comment. Should obviously keep this secure if you list out the whole Account Number or PIN.
I do something very similar but include columns for "outstanding balance", "credit limit" and calculation for "% of credit limit used". I also use mint.com to track my balances and every few days update the outstanding balance on my spreadsheet. This lets me see the % of credit limit used on each card; I never like to have my balance on a given card greater than 50% of credit limit.
I use "code" for my account numbers and PINs (probably decipherable in 2 minutes by a pro

. Also recommend a password in order to open your Excel file.