I use both Mint and Pageonce..I get updated constantly on my cc balances and even notified when ever I get a CLI (thru Pageonce)...
Starting Score: TU 595 EX 600 EQ 585
A third for Outlook. Put all recurring bills and expected receivables in there for tracking. Syncs with the phone. Web access from any computer. Use Mint also for quick and easy checks for all accounts at once.
If you don't have Outlook give Google calendar a try. Or Yahoo as someone suggested. They are easy and free. Will email you reminders also.
I agree with the above post. I use pageonce for my iphone and ipad. it's so cool. they send you an email letting you know due dates, balances, fees charged, etc. The only downfall I've found is that a few of my credit cards are not listed with them so I can't keep up with them on there. Otherwise, it's the best I've found!!! 